Following the first printing of Ptolemy's Geographia in Bologna in 1477, a second set of copper plates were prepared in Rome, also based on the manuscripts of Donnus Nicolaus Germanus, to accompany the 1478 edition published by Calderinus and printed by Conrad Schweynheym and Arnold Buckinck. Shirley suggests that the work on the maps started as early as 1473 or 1474, and the engraving of the plates may well have been finished before the Bologna edition.