Jan Latos (or Latosz, known also under Latinized name as Joannes Latosinus, 1539-1608) is perhaps one of the most controversial and mysterious figures in the debate around calendar reform that took place in early modern Poland-Lithuania at the turn of the 16th and 17th centuries. He openly questioned the astronomical foundations of the reform introduced by the pope Gregory XIII and propagated by Christoph Clavius and thus he got into real trouble. He was first banned to speak freely in 1580’s and for several years he focused on regular astrological practice. At some point in the 1590’s he decided to reexamine the reformed calendar and ignored the ban. In turn he got expelled from the Academy of Cracow and was ridiculed by the Jesuit preachers in their brochures and public sermons, becoming also immediately a synonym of a backwardness and obscurantism. In the modern secondary literature Latosz is usually presented as an example of a scholar who did not have observation techniques and mathematical tools precise and sharp enough to verify the calculations proposed by more advanced astronomers and architects of the calendar reform yet at the same time was stubborn enough to maintain he was right. This attitude lead him to a paradoxical situation in which he found an ally and patron in the person of the Orthodox duke Konstanty Wasyl Ostrogski who was fervent defender of the Orthodox tradition and probably treated Latosz as an useful asset to his own political agenda. Latosz got lost somewhere in the middle of the road between the two calendars: he did not stick to the Julian calendar by all means as he was aware of its errant mechanism yet at the same time he could not accept the reform of 1582. Thanks to Ostrogski’s support he found shelter in the town of Ostróg and become a professor at the local academy but he was also accused of converting secretly to the Orthodox faith or at least being in the Orthodox Churche’s favour.
In my quest for primary sources that constitute the basis of my research I cultivate the belief that even if we do not know what is the exact current location of some manuscripts or unique prints, in case of large number of them it is still reasonable to assume that they will be revealed some day and we will have to rewrite all these footnotes that tell stories about “unknown locations” and “lack of extant copies” of works that could be of great significance to our research if only they had survived the fire, war, flood, robbery and other calamities. In case of Latosz, as only few copies of his works survived until nowadays and his major work on calendar reform, which was supposed to be presented at the papal court in Rome, went missing probably already in the 16th century and most likely never even arrived to the Vatican. While some of his works are still available in a considerable number of copies (this is the case of his Latin Prognosticon of 1594 dedicated to Rudolf II), few of them are known in unique and damaged copies (this is the case of his two astrological prognostications preserved in the Jagiellonian Library in Kraków), and some of them are considered to be irretrievably lost.
This list of irretrievably lost sources might be a bit shorter if we all read carefully the catalogues published by the librarians. By the last September I assumed imprudently that I knew the catalogue of the manuscripts of the National Library in Warsaw pretty well, my list of manuscripts manuscripts I should examine in the next two years of my project is complete and I had the idead what should be done with those I had seen so far. Oh how wrong I was! And how haughty! At some point in early October I took the seventh volume of the catalogue in order to browse the index in search for some name or term I do not even remember right now when to my inexpressible surprise I noticed a familiar name. This was the name of Jan Latosz and it lead me to the “discovery” that the National Library is in the possession of a seventeenth-century copy of the text of Latosz’s Przestroga (A Warning or A Caution), a short astrological and chronological treatise that was originally published in Polish in Kraków in 1595. I immediately ordered the microfilm and checked once again whether the three copies known before 1945 and now considered to be lost have still this status. It turned out that none of these three copies, nor any copy unknown to the pre-war bibliographers was revealed and apparently the manuscript from the National Library is the only witness to this text.
I put aside the list of manuscripts I was goint to examine in the fall semester and delved into the 24 folio pages of the alleged copy of Latosz’s work. With every page my interest grew bigger and bigger and so did my certainty that this document is a credible source for the reconstruction of Latosz’s astrological and chronological views. And I do not even know when I started transcribing its fragments in hope that I will make use of some excerpts, then decided to transcribe the entire text (as you know, part of me is a scribe). As for now I have prepared an article in which I gave the Warsaw manuscript an introduction to the scholarly audience. It was accepted by Terminus, a Kraków-based journal on classical reception and Old Polish studies and should appear soon. I have completed the transcription of the entire manuscript yet it still requires some revisions from the point of view of historical ortography and punctuation. In the nearest future, hopefully this winter, I am going to prepare a critical edition that will be preceded by an introductory essay in which I am going to discuss the ideas presented by Latosz in his treatise and consider some hypotheses on the late, mid-seventeenth-century reception of a text that by any possible rule should have been forgotten by then.
In the second part of the Warning Story (I guess this time it will be a diptych), I will write something more about the contents of the manuscript and a number of questions it raises. As for now, I would like to leave the readers with two things.
The first one is a moral: even if you are sure that everybody is right about the existence or non-existence of a certain source and you trust their authority, go and check it yourself. And read the catalogues from cover to cover. Always. (This may seem as stating the obvious but when one thinks that the whole army of historians, including the author of an entry in the Polish Biographical Dictionary who certainly did a meticulous survey, overlooks the existence of a certain manuscript, perhaps it is worth reminding.)
The other thing is a picture of the opening page of the manuscript. Since the Warning by Latosz is an astrological work which contains [spoiler alert!] some apocalyptic predictions, I thought that the ominously looking photograph of the microfilm of the manuscript will do the job as conclusion:
Jan Latosz, Przestroga…, title page of the 17th-century manuscript copy of a 1595 print (Warsaw, National Library, MS 6631 III)
Chronologia Universalis 