Climate history of the principality of Transylvania during the Maunder Minimum (MM) years (1645-1715 CE)

This paper deals with the climate in the former Grand Duchy of Transylvania, now one of the three major geographical provinces of Romania, within the so-called Maunder Minimum (MM) (1645-1715), an astrophysically defined 10 part of the Little Ice Age (LIA), which was characterized by reduced solar activity. The historical data from Transylvania are compared with that from Germany, Austria and Switzerland. This comparison for the period 1645-1715 shows good agreement but also reveals geographic characteristics of the region. For the first time, we present here a comparison between the four geographic areas in text and tabular form. Quotes from mostly German-language sources are reproduced in English translation. The results clearly help to identify regional climatic differences during the MM. Furthermore, we examine for a longer period 15 (1500-1950) the extent to which the climate of Transylvania might have been affected by long-term fluctuations in solar activity, as deduced from isotopic reconstructions from ice cores. This comparison suggests a certain solar influence but the agreement is not very pronounced. Future investigation in a pan-European context is needed to reach reliable statements. Some results are unexpected – like an unusually small number of severe winters during the last decades of the MM, where extreme cold was restricted to a few years, like the extreme winters 1699/1700 and 1708/1709. 20


Introduction
The period 1645 -1715 is called Maunder Minimum (MM) in solar physics and denotes an epoch of long-term reduced solar activity within the long-known eleven-year activity cycle. The modern discoverer of this seventy-year minimum period was the American astrophysicist John Eddy. He caused a sensation in a paper in Nature in 1976 (Eddy, 1976), especially because 25 he postulated a causal connection with the Little Ice Age (LIA). Since then, the term MM has also been used by climatologists, but not always in its correct meaning. We take the MM strictly as the astrophysical definition of the calendar years from 1645 to 1715.
From the very beginning, when it was recognized, that our climate is not constant, climatic variations were attempted to be related to the Sun (e.g. Herschel, 1801), but the more precisely it became possible to measure solar irradiance, the more it 30 became apparent, that the fluctuations of the solar constant registered so far are too small to directly justify climatic changes.
However, it is generally supposed that the Sun affects the climate indirectly. Usoskin and Kovaltsov (2006) suggested a possible process of ionization by cosmic rays, while Ney (1959), half a century before, suspected an increasing and decreasing frequency of cloudiness due to minor temperature differences.
Over the solar cycle, the irradiance changes mainly in the UV part of the spectrum, which could lead to a weakening and widening of the tropical Hadley cells and to shifts of the subtropical jet streams, or to a shift of the intertropical convergence 5 zone (Vita-Finzi, 2011). Theoretical considerations, however, assume that even in the case of a grand, i.e. long duration minimum, as it is assumed for the MM, no significantly reduced irradiance should have occurred (van Dorland et al., 2006). Therefore, indirect mechanisms, such as changes in air currents and pressure patterns in the troposphere due to different heating of the stratosphere, seem more plausible (e.g. Ineson et al., 2011). In any case, other factors such as volcanic eruptions or the El Niño phenomenon also seem to have a much more drastic effect on cloud formation than fluctuations in solar irradiance. 10 Lockwood et al. (2010) supposed that low solar activity leads to cold winters on the British Isles and parts of continental Europe, while leaving most of continental Europe untouched. According to this study, European climate, lying below the polar jet stream, might be influenced by solar activity, in such a way that it "blocks" the jet stream and thus upholds the mild, humid westerly winds that otherwise characterize English winter. Such "blockings" might push them further north, replacing them with cold, dry easterly winds over parts of Europe. However, it is open to discussion to what extent fluctuations in solar activity 15 change stratospheric winds, given the small magnitude of the changes in irradiance between solar maximum and minimum, and presumably also the MM.
Mounting evidence shows, that the climate of the MMand the LIA in generalwas neither globally synchronous nor regionally coherent (e.g. Neukom et al., 2019), therefore it is necessary to study historical records (and proxy data) from different regions. While several studies from western and central continental Europe as well as from the British Isles have been 20 carried out on the climate of the grand minimum period (e.g. Owens et al., 2017), Eastern Europe has so far been rather neglected. We try to contribute to closing this gap (Stangl and Foelsche, 2020) by studying historical sources in Transylvania.
Results on historical records of solar activity from the same region have just been published in Solar Physics (Stangl and Foelsche, 2021).
Extensive work in order to look Europe-wide into the problem has been done within the frame of the EU project ADVICE. 25 (e.g. Luterbacher et al., 2001;Xoplaki et al., 2001) and important conclusions reached regarding the diversity of the climate of the MM over the different parts of Europe. While it is difficult to compare these results, which include instrumental data as well as sophisticated reconstructions of sea level pressures, with our findings, general patterns regarding the individual years can help to fill in the gaps in a region with sparse data, as it is the case with Transylvania.
In the present paper, we look at the situation in the former Grand Duchy of Transylvania, which was initially dependent from 30 been lacking. To achieve this, we consulted original sources of the time and were therefore able to reconstruct the MM climatically for Transylvania on an annual basis. In section 3 we summarize historical records for the individual years, most often in the form of English translations from German originals, where we try to conserve the original ductus. Further we compare the material from Transylvania with that from Germany, Austria and Switzerland (section 4). And finally, we investigate for a more extended period  whether the climatic conditions of the time in Transylvania actually 5 indicate solar forcing or not.

Study area and historical sources
Transylvania is one of the three major geographical regions that constitute today's eastern European state of Romania and is of comparable geographical latitude with Austria and Switzerland, although the Carpathian Mountains do not reach the heights of the Alps. Today's climate of Transylvania can predominantly be characterized with Dfb (warm summer continental or 10 hemiboreal climate) and Cfb (oceanic climate) according to the Köppen scheme (Szabo et al., 2020). All cities and villages mentioned in the text are given in Romanian language, but are listed in Table 1 in the three major 30 languages spoken within the region, i.e. in Romanian, Hungarian and German. Mountains, rivers and other landmarks appear in their official designations in Romanian, but Hungarian or German names are given in many instances in brackets to ease their identification in historical sources.
The richest sources regarding our study period, i.e. the 17th and 18th centuries, can be found in the southern and eastern part of Transylvania (Sienerth and Wittstock, 1997). Extensive chronicles like those written by Miles (1670) or Kraus (reprinted 35 1862) complement casual notes with relevance for climate history that have been found, among them in the so-called Turmknopfschrift ("poppyhead document") deposited in August 1794 in the poppy head of the Protestant church of Zeiden https://doi.org /10.5194/cp-2021-117 Preprint. Discussion started: 20 September 2021 c Author(s) 2021. CC BY 4.0 License.
(today Codlea) written by the former pastor of this place and afterwards recovered and published about a hundred years later (Draudt 1903). While Matthias Miles (1639Miles ( -1686 describes events from the century preceding his lifetime, he is regarded a very reliable source by historians (Sienerth andWittstock 1997, Stangl 2020). An eyewitness of the events, or at least a contemporary observer for the events he was writing about, was the city clerk of Sighisoara, Georg(ius) Kraus(s) (1607Kraus(s) ( -1679. In 1650 he started with working on his Siebenbürgische Chronik (Transylvanian Chronicle), which deals with local events 5 between the years 1608 and 1665, although the events between 1650 and 1665 get the most intense treatment and occupy about 75% of the whole chronicle. While Kraus is regarded as the most important chronicler of his time, for our purpose of extracting clues with climatic relevance, the clumsy written chronicle of his contemporary Daniel Nekesch Schuller (born in 1606 -year of death unknown) is a somewhat richer source. An important source for our study have been diaries, most notably those by Johannes Stamm, a linen weaver and Paul Benckner, a trader, both from Brasov. 10 The results from Transylvania are confronted with data from Austria, Germany and Switzerland (understood in their current borders). The climatological history of Germany and Switzerland has been extensively studied in monographs by Glaser (2008) and Pfister (1999), while for Austria only local compendia exist and for more limited time spans, most notably the studies of Jäger (2003) for the Tyrol region and Strömmer for the region of Lower Austria (2003). However, extensive older literature and sources exist and many years in our study period are well documented by Pilgram (1788) and Peinlich (1878Peinlich ( , 1882. As 15 for Transylvania, the only extensive historical study is the one by Cernovodeanu and Binder (1993) which is available in Romanian language only. Figure 1 shows the title page of a typical contemporary source, the "Siebenbürgischer Würg-Engel" by Matthias Miles.
https://doi.org /10.5194/cp-2021-117 Preprint. Discussion started: 20 September 2021 c Author(s) 2021. CC BY 4.0 License. Figure 1: Title page of Matthias Miles' Siebenbürgischer Würg-Engel which reads "Transylvanian destroying angel or chronological appendix of the stories that occurred in Transylvania, partly in Hungary and in the other countries bordering on Transylvania in the 15th century AD, from which not only the horrific bloody attacks, wars, and news from various enemies of the country emerge, but also the most secret decisions of all emperors, kings, princes, and voyvods, through which its oppressed fatherland flourished in part, in part completely 5 plunged into the abyss of ruin: in what manner besides the Augsburg confession the rest of the country's accepted religions have emerged." Courtesy Bayerische Staatsbibliothek München. https://doi.org /10.5194/cp-2021-117 Preprint. Discussion started: 20 September 2021 c Author(s) 2021. CC BY 4.0 License.

Annual characteristics of the MM in Transylvania
1645, the first year that solar physicists attribute to the MM, began with an extremely cold winter (Mild, 2010;40). The summer brought a plague of locusts (Armbruster, 1980;394) and severe weather conditions: "On the day of St. John the Baptist (June 24) a large flood of water poured out and caused great damage. On the 11th day in July, the day of Eleneora, there was such a big hail here in Cronen (Brasov) that one thought everything would get destroyed, the fruits of the earth destroyed in the whole 5 field; and then, after a short time there was such a big wind that one thought that everything would go to ruin; great damage has occurred outside in the old town, in the barns and on the roofs. " (Nekesch-Schuller, 1903;229). The winter of 1646 did not seem unusually harsh to people, but on March 29, the cold returned for a short time: "On Maundy Thursday, a substantial amount of snow fell." (Nekesch-Schuller, 1903;230). The summer was very different from that of the previous year. According to Georg Kraus, the city clerk of Sighisoara, there was not a single thunderstorm throughout the summer (Kraus, 1862;165). 10 1647 was notable for inundations (Cernovodeanu and Binder, 1993;123), 1648 by a harsh winter (Cernovodeanu and Binder, 1993;123). In 1649, the winter was very long and severe. From December 6 of the previous year until April, the landscape was continually snow-covered and people, as well as livestock, suffered from the great cold without interruption: "Anno 1649 is starting with a very cold and strong winter, because snow, which fell on December 6 the previous year, remained until April, that is, for 4 months, during which the good grain was completely spoiled." (Kraus, 1862;136). The autumn was characterized 15 by long-lasting rainfall: "Around November, as well as in the previous month, because of the constant rain and pouring water, the soil is so soaked that everything, so to speak, has been swimming in the water; everywhere in Transylvania the roads have become bad, and no one could travel without tying up many additional good horses and oxen, especially through villages and swampy places, such as on the way to Nösen (Nasaud) (...); often, over 30 horses and oxen had to pull; (all of these) were signs of ruin, just as many mountains and hills were broken and devasted in many places, according to the Psalm that the Earth is 20 tired of carrying such brood of hell (even longer); that is a sign of the Day of Judgement." (Kraus, 1862;136).
1650 was apparently an unremarkable year. Only a strong storm in late winter seemed to be worth to report for the citizens of Brasov: "On March 10, there was a terrible great wind at night that one thought everything was about to perish; (It) made a lot of damage to the barns and buildings of the old town and trees were torn down and it also caused great damage to the roofs in 25 the city. " (Nekesch-Schuller, 1903;233). In 1651, the Mures and other rivers caused inundations in January. A late frost at the end of April damaged the fruits: "On April 26, heavy snow fell, which caused (such) a great and violent cold that the vineyards and cherry orchards were completely ruined by frost, as was not often seen at the time, and the cost of a bucket of grain was fl.
[orin] 4.50 and fl. [orin] 3.30 at that time." (Nekesch-Schuller, 1903;233). Strange weather conditions were noted in Sighisoara: "Anno 1651. On May 3, it rained blood here in Segesvar (Sighisoara). In the current year, the time of ripeness 30 came very late, and the cherries and strawberries ripened only in August, and the roses bloomed in September." (Kraus, 1862;183). In 1652, the winter was severe. Swarms of locusts bared the land in Moldova and then covered the ground in winter, partly alive, partly dead. The plague was rampant in the country (Holban, 1968;487). In the town of Medias a thunderstorm https://doi.org /10.5194/cp-2021-117 Preprint. Discussion started: 20 September 2021 c Author(s) 2021. CC BY 4.0 License.
in winter was interpreted as an omen by contemporaries: "Anno 1652. On February 16, in cold winter weather in Medias, very great wind and heavy weather with thunder and lightning hit the Church tower. This and the subsequent weather are once again signs of the ruin of Transylvania. " (Kraus, 1862;188). For 1653, we lack climate-relevant information from the country. It can be assumed that the weather conditions met expectations, particularly that of farmers. In 1654, winter conditions prevailed for more than half a year, namely until April, and beginning with September, the next winter started. "This year has been such a 5 long, violent winter that in Holy Week (at the beginning of April) one could ride a sleigh." (Nekesch-Schuller, 1903;238).
"Nota. When the fruits in the country of Nösen (Nasaud) at the foot of the mountains ripened very late, a lot of snow falls in September and covers everything, so that the fruits have to be searched under the snow and it spoils a lot." (Kraus, 1862;225).
The short summer was characterized by floods: on July 12, the sun was grass-green when it rose; this was followed by cloudbursts, which caused the streams and rivers to overflow their banks (Costin, 1976;166); on August 23 there was another 10 flood (Kraus, 1862;175).
The severe winter that started early did not subside even after the turn of the year to 1655 (Cernovodeanu andBinder, 1993;123). "April 19 brought a lot of snow due to God's punishment, so that in the gardens big fruit trees, grown 20 years ago, were torn from the earth with roots by the hundreds." (Nekesch-Schuller, 1903;239). Also in 1656 the winter is noted as severe 15 (Cernovodeanu and Binder, 1993;123), and the cold of the following winter of 1657 was also harsh, albeit with interruptions.
In the middle of winter, the army of Prince George II Rakoczi could hardly cross the river Tisza. Due to a great inundation, the waters were swelled due to sudden snowmelt in the mountains of the Maramures, but then the cold fell again, and the Tisza froze (Szalardi, 1853;298). In 1658 (Cernovodeanu and Binder, 1993;123), and in the following years, there were many complaints about bitter winter cold. "In October (1658) great snow fell, and did so much damage to the trees in the gardens 20 and in the field, (and) to the fruit. One evil followed the other. Nulla calamitas sola." (Nekesch-Schuller, 1903;239). In 1659, the winter was hard and long (Cernovodeanu and Binder, 1993;123). "So, on May 31 in the night of Pentecost Sunday, it was snowing (so much) that in the morning the trees could hardly be seen; (the snow) melted the next day." (Stamm, 1915;177).
In 1660 the winter was also very cold, but this time it was dry. There was a drought in summer, that was interrupted by sudden 25 cloudbursts (Cernovodeanu and Binder, 1993;90). In 1661, the winter was again severe and lacked snow. The summer was dry too, but the drought was repeatedly interrupted by heavy cloudbursts (Cernovodeanu and Binder, 1993;91). In 1662, the weather was largely similar to that of the previous year (Cernovodeanu and Binder, 1993;123). "An unusual snow fell on October 10, so you had to sow the grain in the snow." (Nekesch-Schuller, 1903;263). Also in 1663, people complained about a very cold winter and the drought of summer, which was very harmful to the harvest (Teleki, 1906 II;528). "March begins, 30 which should drive all evil vapors out of the earth and dry them out by the cleaning wind, but many harmful veils of mist are now emerging." (Nekesch-Schuller, 1903;277). In 1664, winter was no less severe. For the fifth time in a row, there was a dry year, interrupted only by excessive downpours in summer, which also harmed the harvest. "On May 14, a very cold weather comes into (the time of) the flowering of the fruit, and there is also quite a bit of snow for two days; because we oppose God with disobedience, God also sweeps us out of his annual order with the summer becoming winter, whereby the blessings of God are withdrawn from all fruit; but, O Lord, do not go to judgment with your servants, but be kind and gracious to us and promote the work of our hands. ... Bears, big and small, 21, come into the old town and the gardens, do great damage and also hurt a lot of people; and it is to be feared that these bears will become human bears and pull the skin over our ears with the time ... On October 19, a heavy rainy weather mixed with snow develops for almost 8 days." (Nekesch-Schuller, 1903;290). 5 In 1665, the winter was very cold again -"There was a lot of snow in all of Burzenland (Tara Barsei), which did a lot of damage to the fruits." (Konnerth, 2001;112). The summer was plagued by heat and drought (Cernovodeanu and Binder, 1993;123). The year 1666 has been described as a very fertile year (Mild, 2010;46). "It was also a difficult winter this year because the first snow that fell 14 days before Christmas Day (last year) remains very firm and heavy and persistent until March. Such 10 an example (already) happened Anno 1608, and then there is a short and humid summer. Mense Aprili. At this time of spring, there comes a great dryness after the long winter." (Saeculum, 1915;16). 1667 has gone down in history as a rainy year in Transylvania (Cernovodeanu and Binder, 1993;123). "(On) July 22, the weather kills 3 Szeklers [people from Szekely district, Transylvania] in the field in front of Brasov." (Teutsch, 1903b;107). An extremely early onset of winter in Brasov, at the foot of the Carpathian mountains, shocked the people who got snow one day in late summer and their fruit trees suffered breakage; 15 some trees are said to have been knocked down completely: "Anno 1667. Nota bene. On September 12, before dawn, there was so much snow, which fell at night, that many trees with fruit in the gardens were broken, and their roots were torn out." (Stamm, 1915;191). 1668 was also a rainy year, and the warm part of the year was significantly shorter than the cold one.
There was a major flood in Sighisoara at the end of January; the water came into the houses, and people had to flee to the attics (Mild, 2010;46). Between July 24 and August 5, there was constant rainy weather. The Tarnava Mare overflowed its banks 20 and brought floods to Medias and Sighisoara (Toth, 1900;146). "(On) April 1, Easter was with snow and strong wind (and) cold until the Sunday before Pentecost, and there was no sweet rain, but always snow mixed with cold winds. ( ...) from Easter to the day (Ascension Day; May 10) there is always snow and cold wind. July 26, (...) it started to rain until August 15, which resulted in a great flood of water, which you have never seen or heard before in the memory of men, with very great damage to fruit, hay, and grass. Many buildings, houses, and mills are torn in several places, and the rainy weather lasted until August 25 15. Also, in Burzenland (Tara Barsei), 6 people died, and (sic!) drowned." (Teutsch 1915) "Anno 1668, October. After long rainy weather, there is a very nice, dry autumn without rain for a long time. However, quite a bit of snow fell early on October 20. And this year, the wine turned out well in Wallachia and there were all sorts of fruits in abundance." In contrast to the two previous years, drought dominated in 1669. Extreme heat and a wasp infestation prevailed in summer (Holban, 1968;172).
"Anno 1669. From August 6 to November 6, there was no rain in Transylvania; after that, snow fell very early." (Saeculum, 30 1915;19). and wine growing suffered from inundations in summer and frosts in autumn (Benckner, 1903;187). Floods are also reported from the following year 1671 (Cernovodeanu and Binder, 1993;123). 1672, however, was another year of drought; there was price increase and famine (Mild, 2010;48). "Hoc anno is such a drought that you could not grind, but had to use the mortar and handmills." (Teutsch, 1903a;345). In 1673 people groaned under a hot summer, which also brought hail; but there was "a rich harvest of grain and wine". (Mild, 2010;48). In 1674 there was a cold but dry winter; Water shortage everywhere, the 5 mills stopped turning and there was an increase in prices (Mild, 2010;48).
In 1675 the winter was severe and the summer was wet. Landslides and water damage have been reported from everywhere and the grapes did not ripen (Mild, 2010;48). In 1676 a hot summer was recorded (Cernovodeanu and Binder, 1993;123). In 1677 the winter was hard and the summer was rainy (Holban,196;352). 1678 had a very hot summer (Cernovodeanu and 10 Binder, 1993;123) and the Autumn was hot and dry too. "At this time of autumn it hadn't rained for several months and it was very dry weather, so that all you could do was sow in the dust; in the forests (with almost no exception) there were a lot of fires everywhere, which could not be extinguished, and so the most delicate forests burned with the many piles of wood in them, which resulted in no small damage." (Benckner, 1903;199). 1679 was a humid year (Cernovodeanu and Binder, 1993;123). 15 In 1680, as well as two years before, there was a hot summer (Cernovodeanu and Binder, 1993;123), and a severe winter struck 1681 (Cernovodeanu and Binder, 1993;123). 1682 was a year of famine. Furthermore, floods hit the country of Transylvania (Cernovodeanu and Binder, 1993;123). A thunderstorm in late winter was reported in Tara Barsei: "On March 18 there was such a thunder and lightning as they are usually seen in the very highest of summer. This storm also hit a Vlach 20 [Romanian] in Zernest [Zarnesti] together with his wife so that they both died. Afterward, a lot of snow fell. " (Benckner, 1903;202). In 1683, one of the heavy winters was recorded (Cernovodeanu and Binder, 1993;123), which occurred so frequently at that time. Also, in 1684 the winter was rough (Apor, 1863;122). Even south of the Transylvanian Alps, people complained about a very harsh winter in Wallachia (Armbruster, 1980;387). The year was also very rainy. In Moldova, it is said to have rained continuously for four weeks in autumn. And finally, a cockchafer ("May beetle") infestation also occurred this year 25 (Holban, 1968;380f).
hail fell (in Tara Barsei) that the hailstones were as big as a walnut, as this had never been seen before; that spoiled the crops." (Konnerth 2001;114).
In 1690, locusts invaded Moldova in such numbers that the sun was said not to have been seen for two months (Holban, 1968;118f). Then they invaded Transylvania and darkened the sun over today's Cluj-Napoca. The summer was very hot (Toth, 1900;5 327). "After a year of drought, there was again a terrible famine and price increase in Biertan." (Janesch, 1989;138). In 1691, on May 24, a terrible storm struck Sibiu, Brasov, and Codlea, and on June 26, there was a devastating hailstorm; a little later, locusts invaded the country, and it was very hot and dry (Seyberger and Blasius, 1918;441). "On the day of the Ascension of Christ (May 24) a fierce storm developed and moved over the Carpathian Mountains near Sibiu, where it divided. In Bucharest, it did great damage by striking the royal castle and lighting the powder in a tower, smashing nearby buildings. Still, the other 10 (thunderstorm) approached our Burzenland (Tara Barsei) and threw a thick hail to the fields, which smashed all the grain in the field of Zeiden (Codlea) down to the roots, killing even crows, sparrows, and other small birds so violently that all the furrows and fields were full of skeletons; in some places, the earth was covered to the height of half a cubit. But the hailstones resembled a big chicken egg and could not melt in many days." (Annotata, 1903;301). In 1692, there was drought. In August, a large number of locusts moved across the authorities of Hermannstadt (Sibiu) and Mühlbach (Sebes) (Draudt, 1903;88f). 15 1693 was also a dry year. A cockchafer plague was followed by whole "clouds" of locusts that moved across the country. The summer was exceptionally dry (Apor, 1863;130). Inundations are reported from 1694 (Cernovodeanu and Binder, 1993;123). 1695 was also characterized by floodings (Cernovodeanu and Binder, 1993;123). In autumn of that year, a cold spell damaged the wine cultures: "October 5, the cold spoils the wine." (Teutsch, 1903c;408). Calamities have also been reported from 1696: 20 on May 14 hoarfrost (Breitner, 2005;146), later floods (Cernovodeanu and Binder, 1993;123). "On August 21, great hail fell on the field of Zeiden [Codlea], Brenndorf (Bod), and Heldsdorf (Halchiu), which injured people and killed many birds and threshed the grain" (Teutsch, 1903b;115). In 1697, there were inundations (Cernovodeanu and Binder, 1993;123), while in 1698, the summer was particularly hot (Cernovodeanu and Binder, 1993;123). In 1699, torrential rain fell over Transylvania between June 2nd and 5th. Particularly in the administrative district of Sibiu and in the mountains of the Siebenrichtergebirge 25 (Muntii Lotrului) there were violent cloudbursts so that the river Cibin inundated the fields and flooded the swamps and ponds outside the city walls of Sibiu; the mountain streams of the so-called Transylvanian Alps south of the city swelled to torrents, which tore down mills and huts. In Sibiu itself, pouring streams flowed through the alleys, and water entered the houses through doors and windows (Fuchs and Lupinus, 1848;284).

30
In 1700 there was a very severe and prolonged winter; only in April did the snow melt (Bielz, 1862;57). Also the 18th century began with the grim winter of 1701 (Cernovodeanu and Binder, 1993;205). In 1702 there was rainy weather all over the country and large, "never heard of" inundations (Rhethly II; 28). 1703 was a dry year (Cernovodeanu and Binder, 1993;205) and even more 1704, where "terrible drought" is mentioned. (Rhethly II; 28). testimony from Transylvania. Still, beyond the border, in Moldova, the air was so filled with flying locusts that they darkened the sunlight like clouds (Camarian, 1965;23). In 1708, the weather was extremely dry (Cernovodeanu and Binder, 1993;205), and the winter was so mild that it was practically non-existent at least at the beginning of the year: "Anno 1708. Just as we had ended the past year with a lovely summer's day, we started this one with the most pleasant spring weather and brightest 5 sunshine; the oldest people in this city testified, not without surprise, that during their lifetime they had no idea of such May weather in the winter months." (Christophori, 1915;289). There was no rain in Honigberg (Harman) from August 21 to October 11 (Konnerth, 2001;115). As extremely mild as the winter was that year, it showed itself from the grim side in the following of 1709: "It is so cold at the beginning of the year that many people, cattle and trees freeze to death, and the waters freeze to the bottom (Teutsch, 1903d;178). In June, locusts invaded Transylvania via the Bran pass (Armbruster, 1980;395). "When 10 Charles XII (of Sweden) fled to Bessarabia this year, there were swarms (of locusts) from the Black Sea that rose like a storm wind and fell like hailstorms that his infantry and cavalry could neither see, nor get away." (Pilgram, 1788; 314).
In 1710 there was a terrible drought accompanied with unbearable summer heat; in Moldova locusts filled the air, darkening the sky and causing a terrible roar. They left the forests bare as if it were winter (Holban, 1968;317f). When they came to 15 Transylvania, they began to kill each other, so that people waded in their carcasses up to the ankles (Cserei, 1852;441). "Again the strongest springs dried up and also many water-rich rivers in such a way that one had big problems with grinding." (Teutsch, 1903d;178). The drought also had tragic consequences due to superstition: "(On) August 15, a weather maker from Wolkendorf (Vulcan), had put in the spring the dew from 3 meadows into a sack of leather so that it would not rain for a long time. A prolonged heat followed this in Rosenau (Rasnov), so she was sentenced to death in prison ... On September 21, white 20 and red roses bloomed, and in some places, the fruit trees also bloomed like in the spring." (Seyberger and Blasius, 1918;458). 1711 was a year with another plague of locusts, probably because of the weather: In Moldova, people complained about unbearable heat and drought in summer (Holban, 1968;559ff), while in Transylvania floods in the area of the so-called Drei Stuehle took many mills with them; The damp weather also caused the grapevines to rot, and only little and inferior wine was made (Cserei, 1852;475). In 1712, after inundations in spring, an exceptional drought occurred and led to a poor harvest 25 (Acsady, 1896;371). In autumn, locusts fell in again and hibernated in the Maramures region. In 1713 there was no sign of dry conditions. On the contrary: inundations were reported in summer (Rethly, 1970 II;57f). In 1714, however, from February 28 to June 20, there was no rainfall in the whole country, causing the grain to spoil. (Teutsch, 1903a;348). 1715, the last year of significantly reduced solar activity, was rainy in Transylvania (Acsady, 1896; 319). 30 We note that quite some years during this period had harsh wintersbut also dry summers, which is compatible with a higher frequency of blockings (cf. Luterbacher et al., 2001), however, this was apparently not a continuous feature of the entire period at least not in Transylvania (see also

Annual comparison with data from Germany, Austria and Switzerland
In the following, the geographical regions Germany, Austria and Switzerland are understood in terms of their current borders, unless otherwise noted (the results are summarized in Table 2 at the end of this section).
While the winter of 1645 was described as exceptionally cold in Transylvania, Germany had average conditions (Glaser, 2008;150). However, in Styria, in Austria, there was a freezing winter (Peinlich, 1882;321), and in Switzerland, the lakes were 5 mostly frozen in January and, there was snow in the lowlands (Pfister, 1999;104). The winter of 1646, was described in Germany and Austria (Peinlich, 1877;I.515) severe like the one in Transylvania, while the dryness that was rather hinted than complained in Transylvania was lamented throughout Europe (Pilgram, 1788; 175). 1647 was a rather inconspicuous year in Germany. The inundations that occurred in Transylvania found their counterpart in Vienna, when the Danube flooded its banks in August after days of rainy weather (Pilgram, 1788;150). 1648, the year in which the terrible Thirty Years' War ended with 10 the Peace of Westphalia, brought an average winter to Germany (Glaser, 2008;151), so the severity of the Transylvanian winter this year may be somewhat overstated due to the lack of quantification. The severeness of the Transylvanian winter of 1649, however, is supported by reports from Germany, where it also lasted until April and where wolves invaded the villages.
And, just as in Transylvania, autumn was described as cold and wet (Glaser, 2008;152). In Switzerland and Austria, however, no exceptional conditions were noted. 15 1650 was an average year in Germany with rather mild winter conditions (Glaser, 2008;153). Even in Switzerland and Austria (Pilgram, 1788;150), the year was not climatically noticeable, which is in good agreement with the reports from Transylvania.
In 1651, there were no unusually cold winter conditions in Germany (Glaser, 2008 153), Austria (Pilgram, 1788; 252), and Switzerland. From late spring to mid-May, cold weather was also recorded in Germany, accompanied by rain, hail, and even 20 snowfall (Glaser, 2008;154), which corresponds to the above-quoted report by Nekesch-Schuller from Transylvania. The severe Transylvanian winter of 1652 cannot be confirmed in Germany, Switzerland, and Austria. On the contrary: in Germany, the winter was exceptionally mild that year (Glaser, 2008;154). The year 1653, missing from our collection of Transylvanian sources, has not been noticed as unusual in Germany, Austria, and Switzerland either, which may explain the silence of the Transylvanian chroniclers about the weather this year. 1654 was either less cold in Germany than in Transylvania, or the 25 chroniclers forgot to mention a few warm periods. Glaser (2008;154) stated that the first half of winter was characterized by temperatures well above average. The river Main did not freeze until mid-February, and the winter cold continued through March. The following winter started in Germany at the end of November, two months later than in Transylvania.
The harsh winter of 1655 is confirmed by Austrian sources (Peinlich, 1877;I.535, Pilgram, 96), while Germany shows the 30 differentiated picture of a changeable winter with alternating warm and cold periods (Glaser, 2008;155). The situation is similar within the subsequent winter of 1656. Austria also reports it as strict (Peinlich, 1877;I.537), while Glaser for Germany has very different regional conditions. Only in southern Germany, according to the sources, does the winter seem to have been severe (Glaser, 2008;155). Even in 1657, winter conditions were quite different regionally. The winter in Germany was generally mild and rainy, but not in East Prussia, where a severe winter is reported. (Glaser, 2008;156) Winter was also harsh in Austria, at least in the province of Styria (Peinlich, 1877;I.537). 1658 had an extreme winter, and in large parts, especially in Germany, it was long and snowy. The cold was so great that this year's winter is considered to have been one of the worst.
The Baltic Sea was frozen, wolves, and other wild animals invaded villages and towns. Even the great rivers and streams froze 5 over. In this respect, it may come as a surprise that the Transylvanian winter was described as harsh, but not as outstanding compared to other contemporary winters or the following one in 1659, which was not particularly severe in Germany, but a lot more in Austria. Peinlich stated, "It was even colder (than the last) winter. The wine was freezing, that you had to split it with axes." (Peinlich, 1877;I.537).

10
In Germany (Glaser, 2008;158) and Italy (Pilgram, 1788;96), the year 1660 was counted among the harsh winters, and the so-called "Seegfrörne" (freezing of the lake) occurred at Lake Constance, meaning that it froze on the surface. As far as the drought of the year is concerned, there was no complaint about it in Central Europe, Glaser (2008) notes that the summer was characterized by good weather and little rainfall. 1661 was also a dry year in Transylvania, but in Germany this was only valid for spring and the first half of summer. In winter, the conditions were felt to be exactly the opposite. While it was portrayed as 15 strict and dry in Transylvania, Glaser considers the winter in Germany as very mild and humid. Even in 1662, the winter in Germany and Austria (Peinlich, 1877;I.541) was remarkably mild, while in Transylvania, it was counted as a harsh one. The lack of snow reported from Transylvania was also reported from Bohemia (Peinlich, 1877;I.320). In 1663, the winter in Germany was characterized by extremely low temperatures and an abundance of snow (Glaser, 2008;158). The drought of the Transylvanian summer found no counterpart in the German countries, on the contrary: June was rainy, stormy and cold there. 20 At the beginning of July, there was warm summer weather for a few days, after which rainy and cool conditions set in. It was only in autumn that it became warm and dry. Also, in 1664 conditions were experienced rather differently in Germany than in Transylvania. Only the cold of the second half of winter was also felt in German countries. The year began mild in Germany, but severe winter cold set in in mid-January. Spring and summer were not uncommon, but autumn was characterized by cool and rainy weather (Glaser, 2008;159). 25 In 1665, the correspondence of the conditions in Germany, Austria, and Transylvania is evident. A freezing winter and a hot summer were noted in all three regions. (Glaser, 2008;160, Pilgram, 96). However, the year 1666, was, compared to Transylvania, completely different in Germany, Austria, and Switzerland, where the striking feature was a summer characterized by extraordinary heat and extreme drought (Glaser, 2008;160, Pilgram, 175, Pfister, 131). There is no mention 30 of a harsh winter there -on the contrary: Germany experienced an ordinary winter with a rather mild character (Glaser, 2008;160). 1667 was also a rainy year in Austria (Pilgram, 1788;151). Summer cold was reported in Switzerland, and in mid-June, there was knee-deep snow in the hilly country of Central Switzerland (Pfister, 1999;144). The onset of winter in Germany was later than in Transylvania, but still early: In the middle of November, suddenly heavy snowfall set in (Glaser, 2008;160). the harvest had to be postponed to September. December was so mild in the east of the German Empire that the flowers came out. At Ulm, however, the Danube froze at the turn of the year (Glaser, 2008;161). Overall, the conditions were not unlike those in Transylvania. The exceptional drought and summer heat of 1669 was confirmed in Germany (Glaser, 2008;161) and Switzerland (Pfister, 1999;131). Despite inundations in Tyrol in July, the Austrian summer seems to have been similar; 5 Pilgram particularly highlights the excellent wine of this year (Pilgram, 1788;252).
The summer of 1670 was also rainy in Austria (Peinlich, 1878;II.440), but in Germany it was pleasantly warm (Glaser, 2008;161). While the chroniclers in the Principality of Transylvania did not complain about winter cold this time, a hard winter was reported from Germany (Glaser, 2008;161) and Austria (Peinlich, 1878;II.440). The inundations that hit Transylvania in 1671 10 found their counterparts in Friuli (Pilgram, 1788;151). In Germany this year attracted attention due to its mild weather all year round (Glaser, 2008;162). 1672 was in Germany and Austria completely contrary to the conditions in Transylvania. From mid-July, rainy weather appeared in Germany and more or less characterized the rest of the year (Glaser, 2008;162). It was a cold and wet summer in Austria (Peinlich, 1877;I.552). The situation was similar in the following year 1673, when the summer was dry in Transylvania but wet in Austria, Switzerland, and Germany, where the summer was also cool (Glaser, 2008;162). 15 In Switzerland, rains at the beginning of summer led to inundations (Pfister, 1999;161). As a result of constant rains in Austria, the Inn River flooded its banks, followed by the Danube in July, while in Germany the Elbe inundated in August (Pilgram, 1788;151). In 1674, winter was hard in Germany. The three winter months were frigid, and the sea froze on the coasts (Glaser, 2008;163). In western Central Europe, there was no trace of the drought prevailing in Transylvania, on the contrary, it was a very wet year in particular in Bohemia (Peinlich, 1877;I.552) and the wine yields were few and poor (Pilgram, 1788;252). 20 In June 1675, snow lay in Bern. In July, people went out with thick jackets, and in August, snow fell in the village of Einsiedeln at 880 m above sea level. Higher alpine pastures remained buried under the snow cover all summer (Pfister, 1999;156). In southern Germany, winter was abnormally warm. Flowers are said to have grown in mid-January. Spring was rainy, and cool, wet weather and inundations prevailed in summer, so the wine was bad and sour (Glaser, 2008;164). The summer of 1676 25 brought beautiful, warm weather to large parts of Germany (Glaser, 2008;164) and Switzerland (Pfister, 1999;156). The vintage quality was praised in Austria (Pilgram, 1788; 252), which indicates a hot, dry summer as it was experienced in Transylvania. The winter of 1677 was not perceived as exceptionally cold in western Central Europe, although it varied widely from region to region in Germany (Glaser, 2008;164). In Switzerland, the late summer was dry and yielded good wine (Pfister, 1999;166), but in Germany, the summer was cool so that the wine was only mediocre (Glaser, 2008;164). 1678 was also 30 extremely hot and dry in Germany. The grape harvest started early, and the wine tasted excellent (Glaser, 2008;165). In Austria, the summer was hot, but not dry (Peinlich, 1877;I.130). The wet annual characteristic of 1679 in Transylvania matches the reports from western Central Europe. According to Glaser (2008;165), the summer in Germany was stormy and rainy, and about the unstable weather and frequent rain, which arose from the great plague that broke out here in mid-July. So the spring, and (at least) the first part of summer was damp." In 1680, in Germany, people complained about the heat and drought starting in July (Glaser, 2008;165). A very dry autumn, in which the temperatures were so high that the pear trees could be seen blooming again, was recorded in Switzerland (Pfister, 5 1999 166). Quantitatively good vintage is reported in Austria. (Pilgram, 1788;252) In 1681, winter was extraordinarily cold in Germany, as was the spring. Increasing drought and heat, which then became extreme in summer, plagued Germany and Austria (Peinlich, 1878;II.131) and Switzerland (Pfister, 1999;166). In the mild winter of 1682, inundations occurred in Germany (Glaser, 2008;166). Austria experienced "unfortunate weather, its main character was wetness, even in summer; pestilence." (Peinlich, 1878;II.131). In 1683, winter in Germany was only of average cold, or even too mild regionally; only 10 in East Prussia was it clearly severe (Glaser, 2008;166). Lake Traunsee in Austria was frozen (Strömmer, 2003) and even the water near the coasts of the Adriatic is said to have frozen. (Pilgram, 1788;97). In England, this winter was so cold that the Thames got 11 inches of ice (Peinlich, 1878;II.460). The subsequent winter of 1684 was extreme in all German-speaking countries. In Germany, it was "cruelly cold" and fairs were held on frozen rivers. At the end of March, there was ice on the streets in Königsberg (Kaliningrad) (Glaser, 2008;168). In Switzerland, wine turned to ice in January and February, and trees 15 split with a loud bang (Pfister, 1999;92). Heavily loaded wagons moved across the frozen Rhine, and Lake Constance could be traversed from Hagenau to Münsterlingen on foot (Pfister, 1999;93). Also in Austria, the cold was noted as "extraordinary" (Peinlich, 1878;II.137).
In 1685, the reports from Germany and Switzerland confirm the news from Transylvania again. Only in Austria, the winter 20 cold seemed not worth mentioning to the chroniclers. In Germany, the winter was very severe, and Lake Constance froze as in the previous year. The sea at the coasts was covered with ice, and it was snowing on many days. Storms and snowfalls lasted into April, and there was still ice on the streets of East Prussia until the middle of the month (Glaser, 2008;168). The cold winter of this year did not seem to end for people in Switzerland either. Rivers and lakes were covered in thick ice. Even in the middle of the summer, on July 26th and 27th, it was still snowing at lower altitudes, even in Zurich (400 m above sea 25 level), snow is said to have fallen (Pfister, 1999;102). In 1686, winter was only in Transylvania considered to be very long.
In Germany, the winter was also very mild (Glaser, 2008;169), and from Switzerland, we even find the opposite of what the Transylvanian chronicler reports. Vegetation started very early, at least in the eastern Alpine valleys. Austria only commemorates a good wine year (Pilgram, 1788;253), which agrees well with the Transylvanian summer drought. he summer was also hot in Germany (Glaser, 2008;169). The unusual cold that hit Transylvania at the end of May 1687 had its counterparts 30 in Germany and Switzerland. In the first part of April, it snowed almost every day in Leipzig, but it suddenly became very hot in May. In summer, cool and rainy weather dominated, as in Transylvania (Glaser, 2008;169). In Switzerland, there was snow throughout April in the village of Einsiedeln at 880 m (Pfister, 1999;113). From Austria we learn about an "excellent summer with wine and fruit in such abundance that the branches broke under their load; afterward, rainy." (Peinlich, 1878;II.143). The https://doi.org /10.5194/cp-2021-117 Preprint. Discussion started: 20 September 2021 c Author(s) 2021. CC BY 4.0 License.
cold Transylvanian winter of 1688 did not have a counterpart in western Central Europe. There was an average winter in Germany (Glaser, 2008;170), and it was not considered to be unusual in Austria and Switzerland either. In 1689 the spring was cold and wet in Germany, but summer was warm and dry (Glaser, 2008;170). In Switzerland and Austria, the year was primarily characterized by many avalanches in winter (Pfister, 1999;Peinlich, 1878, II.461).

5
"Huge locust swarms in Hungary" (Peinlich, 1878;II.145), are mentioned in 1690 on the occasion of the description of that year's wet summer in Austria. The year was also marked by moisture in Germany, although the summer varied from region to region (Glaser, 2008;170). The hot and dry summer in Transylvania and the generally wet weather conditions in western-Central Europe may have been responsible for the fact that locust swarms accumulated in extreme density in Eastern Europe.
While the summer of 1691 was rainy in Germany (Glaser, 2008;171), it was rather dry and hot in Austria. Throughout the 10 summer, there were violent thunderstorms without cooling the air (Peinlich, 1878;II.147). The conditions were not unlike those in Transylvania, but locusts again spared Europe's western parts. In 1692 they also haunted Transylvania but spared the Holy Roman Empire, where the summer was generally rainy and chilly (Glaser, 2008;172, Pilgram, 152). In the following year, 1693, summer drought and heat also prevailed in western Central Europe (Glaser, 2008;172;Jäger, 2003;114), so that locusts penetrated Austria (Peinlich, 1882). In 1694, Germany experienced a cool and rainy summer (Glaser, 2008;173). From 15 Austria, it is mentioned that the wine was not only sour but also very little (Pilgram, 1788;253). In Tyrol, the year was wet and cold. In the Bolzano area, however, summer was said to be hot and dry (Jäger, 2003;162).
The summer of 1695 was cool and rainy in Germany (Glaser, 2008;173). Pilgram (1788; 253) notes "Miserable Wine" for Austria. The conditions were similar to the Transylvanian. Poor conditions characterized the whole of June in 1696, but 20 summer became warm and pleasant, at least in southern Germany (Glaser, 2008;174). 1697 stood out in Western Europe due to an extremely cold and snowy winter (Glaser, 2008;174, Pilgram, 97, PGPS, II.151). Spring was normal in Germany, summer unstable, and wet and stormy weather prevailed at harvest time (Glaser, 2008;174). In 1698, conditions seem to have been contrary between the Holy Roman Empire and Transylvania. A long, heavy, and snowy winter was reported from Germany and Switzerland. Wet and cold weather dominated the rest of the year, and the wine tasted terrible (Glaser, 2008;175). In 25 1699, Transylvania was incorporated into the Habsburg Empire, but in terms of climate, the year was unremarkable.
Not only in Transylvania was the winter of 1700 extreme. In Austria, people and livestock froze to death, and even the fish in the ponds perished. "On March 15, it was still so cold that the spittle turned to ice before it fell to the ground." (Strömmer, 2003;101). In Tyrol the temperatures likely dropped to below -30 °C, since some church bells cracked. In February there was 30 also a lot of snow (Jäger,265). It did not look any better in the north of the continent: "The Baltic Sea was covered with ice 10 miles from the coasts." (Strömmer, 2003;101). A harsh winter did not open the new century in Central Europe like it did in Transylvania. In Germany, it frequently rained in the winter of 1701 (Pilgram, 1788;207), while in Austria, high temperatures and exceptional drought dominated the year (Strömmer, 2003;101). Only in Switzerland, especially at higher https://doi.org /10.5194/cp-2021-117 Preprint. Discussion started: 20 September 2021 c Author(s) 2021. CC BY 4.0 License.
altitudes, was there a lot of snow in April (Pfister, 1999;114). The rainy year 1702 had its equivalent in Italy, where it rained almost continuously for four months, beginning at the end of February. On the other hand, great drought was reported from Austria as in the previous year (Strömmer, 2003;102). Neither exceptionally dry nor exceptionally moist conditions were reported from Germany and Switzerland. In 1703 the wine became excellent in Austria "despite" an extreme drought (Strömmer, 2003;103). While the dry conditions in Transylvania continued in 1704, and Italy also suffered from July to 5 October, summer in Switzerland was regarded as pleasant with sunny weather and not excessive warmth. In Austria, some witnesses considered the year to be even a rainy one, especially in Styria (Pilgram, 1788;153).
1705 was rainy in Transylvania, and also Austria had wet conditions most of the year (Pilgram, 1788;153). In Switzerland, conditions have been more differentiated: July was hot, and August was also dry with pronounced summer heat, and there was 10 very little snow in the high mountains. In October, Foehn storms swept across the Alps (Pfister, 1999;169). 1706 was also a humid year in Transylvania. In Austria, however, at least winter and spring were very dry (Strömmer, 2003;104). 1707 seems not to have been exceptional in Central Europe, while the strikingly mild Transylvanian winter of 1708 also prevailed in Germany (Glaser, 2008;181) and Austria. However, there also occurred heavy snowfall there regionally (Strömmer, 2003; 105). Richard Peinlich clarifies: "It was so mild in the winter that the flowers bloomed around Ödenburg (Sopron) in February, 15 but one day the cold in Styria was so strong that the wine froze in Pettau (Ptui)." (Peinlich, 1878;II.156). The severeness of the winter of 1709 prevailed in large parts of Europe, where it became known as "great frost" or "great winter". Glaser mentioned an extremely harsh winter for Germany (Glaser, 2008;181), Peinlich in Austria called it the "coldest winter in a hundred years; the length and roughness of the same is said to be extraordinary everywhere; snow still fell in Ödenburg on May 17". (Peinlich, 1878;II.157). In Switzerland, the cold in January was so great that the cattle were taken into the parlors 20 in some places to save them from freezing to death. Birds are said to have fainted on the ground so that they could be caught by hand (Pfister, 1999;102).
The year 1710 brought extreme drought to Germany, but only in autumn (Glaser, 2008;182). In contrast, the following year, 1711, in western-central Europe was slightly humid in western Central Europe (Pilgram, 1788;153;Strömmer, 2003;108). 25 1712 was unremarkable in Germany and Switzerland. In Austria, the harvest failed as in Transylvania, but for a different reason. There were frequent storms in summer. The wine became delicious but was available only in very reduced quantities (Strömmer, 2003;108). "Very changeable weather, so the harvest is bad", is reported from the province of Styria (Peinlich, 1878;II.178). The summer floods in Transylvania in 1713 had their equivalent in Austria. After a rainy May, there were inundations in June, which destroyed mills (Strömmer, 2003;109). The dry conditions of 1714 did not show up in western 30 Central Europe. The weather in Germany, Austria, and Switzerland was very unstable and precipitation was rare (Glaser, 2008;183). In 1715, the conditions were finally rainy, not only in Transylvania but also in Austria, at least in summer. Winter was temperate and dry in the province of Styria, but after that, the weather was even more changeable and unhealthy than last year's (Peinlich, 1878;II.230 Table 2 shows the main weather characteristics for every year of the MM in Transylvania and the correspondences of the listed phenomena for Germany, Switzerland, and Austria. All entries were discussed here in the text, and the respective sources were given.

The decades before and after -comparison with the fluctuations in solar activity
As part of FWF project P 31088, we have created a still unpublished database that traces the climate of Transylvania down to 5 the year 1500 CE in almost annual resolution (Stangl and Foelsche, 2020). From this data set, we counted the reported unusually cold or mild winters (Fig. 2) and particularly hot or cool summers per decade (Fig. 4) and compared these numbers with a graph of the reconstructed strength of the solar activity (Fig. 3), as published by Wu et al. (2018), which ends in 1889.
For the later decades up to 1950, we used the annual SILSO sunspot numbers (Sunspot Index and Long-term Solar Observations, source: Source: Royal Observatory of Belgium, Brussels; Clette, and Lefèvre, 2016). While decades are usually 10 counted starting with the year "1", there is an alternative counting that defines decades from the 0 years to the years ending with 9. Since the reconstruction by Wu et al. (2018) uses the latter, we also adopted this scheme for better compatibility.
Two large and two small minima of solar activity fall within the investigation period. The two large ones are the Spörer Minimum (1450-1540) and the Maunder Minimum (1645-1715), the two small ones are known as the Dalton Minimum (1790-1830) and the Gleissberg Minimum (1901)(1902)(1903)(1904)(1905)(1906)(1907)(1908)(1909)(1910)(1911)(1912). 15 It is commonly believed that in years of high solar activity, temperatures on Earth will rise, and mild winters and hot summers will increase in frequency. In contrast, the number of severe winters and cool summers is expected to increase with decreasing solar activity. Although the historical data from Transylvania certainly do have specific gaps and are subject to a certain subjectivity of their reporters, a comparison can be risked after all. Only the decades around 1825, 1845, and 1855 contain such sparse concrete information that the specified climate values are fraught with high uncertainty. 20 When comparing the top panel of Fig. 2 (number of hard winters) with Fig. 3 (solar activity), we can see an accumulation of severe winters in the time of the abating Spörer minimum (note that this minimum is only partly covered by our data) and also over long periods of the MM. In contrast, for the less pronounced Dalton and Gleissberg minima, no accumulation of cold winters is noticeable. However, it should be noted that there is no convincing correlation, since the number of exceptionally cold winters has also high peaks in the middle and at the end of the eighteenth century and even after 1920 when the solar 25 activity was high to very high.
Let us consider the bottom panel of Fig. 2, which shows those winters that the contemporaries considered exceptionally mild.
A "negative picture" of the top panel of Fig. 2 would be expected this time: high numbers at times of high solar activity. The    Wu et al. (2018), while actual sunspot numbers (directly observed or photographed) were used for the later decades (SILSO data, Royal Observatory of Belgium, Brussels).

5
The top panel of Fig. 4 shows the cool summers of the examination period. Their accumulation should again go hand in hand with low solar activity. In fact, the peaks from 1665-1675 fit well the most pronounced phase of the MM. Otherwise, the remaining peaks appear without exception at times of high solar activity.
The bottom panel of Fig. 4 finally shows the hot summers, the peaks of which should correspond to the peaks of solar activity.
While for the time between the Spörer and the Maunder Minimum the agreement is quite good and likewise for the time 10 between Maunder and Dalton Minimum, it must be noted that distinct peaks fall in the very middle of the MM, where none were to be expected.
Although the data presented here for the Transylvanian climate suggest a certain degree of influence from long-term fluctuations in solar activity, one must remain extremely cautious in their interpretation. At best, one could see this as an indication and wait for future evaluation of climate data from the entire German-speaking area. From a European perspective, 15 Transylvania is only a small province, and the data are much sparser than for Germany, Austria, or Switzerland. Besides, we would like to emphasize that previous studies in this area, which had data on a much larger, and geographically broader basis, have not led to any convincing results regarding solar forcing (van Dorland, 2006). The sometimes seemingly striking agreement in parts of the curves presented here may, therefore, be purely coincidental.

Summary and conclusions
For our work, we selected the period of the Maunder Minimum (MM, 1645(MM, -1715, an astrophysically defined section of the Little Ice Age (LIA), and compared the historical data from the Grand Duchy of Transylvania with those from Germany, Austria and Switzerland. For the first time, we present here a comparison between the four geographic areas in text and tabular 5 form. Quotes from mostly German-language sources are reproduced in English translation. There are numerous similarities, but also geographic differences, so that a convincing picture emerges of the weather conditions prevailing in a region that until 1699 was somewhat outside and then just within the borders of the Habsburg Empire.
Furthermore, for a larger period (1500-1950), we examined on a decadal basis the extent to which an influence on the climate of Transylvania through long-term fluctuations in solar activity, as was inferred from isotope reconstructions from ice cores, 10 can be seen. With the exception of the years 1820-1830 and 1840-1860, we had sufficient historical data to be able to count the frequencies of hot and cold anomalies in the respective summers and winters reliably, so that a picture emerges which decades were characterized by warmth above or below average in the respective seasons. Although this comparison shows some promising result, which suggests a certain solar influence, further studies in the pan-European context have to be awaited in order to arrive at reliable statements. Transylvania alone is an area that is too small and not sufficiently covered by data in 15 terms of climate history, so far-reaching conclusions from this material alone cannot be drawn. However, the results clearly help to identify regional climatic differences during the MM. Some results are unexpectedlike an unusually small number of severe winters during the last decades of the MM, where extreme cold was restricted to a few years, like the extreme winters 1699/1700 and 1708/1709. 20