Green, Jonathan, and Oliver Duntze. “Johannes von Glogau and the Earliest German Practicas: On the Dating and Authorship of Fragmentary Prognostications.” Gutenberg-Jahrbuch 88 (2013): 68–85.When I was revising chapter five of Printing and Prophecy, "Practica teütsch," on astrological prognostic booklets, I noticed that there were a few early practica authors whose work I hadn't seen, so I ordered facsimiles. There was also an anonymous fragment in Berlin, dated no more precisely than 1474-78, possibly the earliest German practica of them all, so I ordered images of it as well. Once they arrived, I glanced at them. They didn't seem to change the chapter, so I moved on.
Last spring I took a closer look at the fragment, which consists of two unfolded sheets. If you virtually reconstructed the resulting gathering, what would it look like, and how would the text be organized? Were there any datable astronomical facts?
It turned out the fragment might be datable, and the sequence of chapters looked quite similar to the sequence used by Johannes von Glogau. As stereotyped as practicas were, individual astrologers often had their own particular style, especially in the early period before the genre conventions were fully established.
I asked Oliver what he thought. He provided some useful corrections. He also pointed out another undated fragment that followed a similar sequence of chapters. Could it be dated as well? We decided it could, and so a joint research project was born, culminating in the article that just appeared in Gutenberg-Jahrbuch.
For dating fragments like these, which turn up with some frequency, we make two methodological contributions. In combination with typographic analysis, diving into the arcana of early modern astrology often permits a precise dating. Also, familiarity with the authors' individual styles will sometimes permit attribution to a particular author.
Consequently, we were able to date the earliest German practica to 1477 with possible manuscript evidence of another for 1476, all by Johannes von Glogau. This points to the route by which printing astrological booklets came to German lands, shows how important the vernacular was even in the earliest period, and makes German practicas somewhat more like contemporaries rather than late imitators of the Italian astrologers.