The artist who carried the concept of the new fortifications out of Italy into northern Europe was Albrecht Dürer upon his return from his studies in Italy. He published a refinement of his military thoughts in 1527. Although he illustrated outmoded notions such as the rounded bastion (“roundel”), his was the first printed work on permanent fortification and was seized upon by soldierly minds, in particular, the Dutch.
Dürer was not the only artist of the time with a strong interest in defense innovation and architecture: there was of course Leonardo DaVinci and, surprisingly, Michelangelo Buonarotti who in 1545 vented this acidic remark to Antonio da Sangallo the Younger: “I don’t know very much about painting and sculpture, but I have gained a great experience of fortifications, and I have already proved that I know more about them than do you…” (This from the man who sculpted David and the Pieta, painted the Sistine Chapel and spent the final 12 years of his life as the primary architect for the new St. Peter's in Rome.)