In 1527 Albrecht Dürer (1471 – 1528) published a treatise on fortifications, Etliche underricht zu Befestigung der Stett, Schloss und Flecken (Several instructions for fortifying towns, castles and small cities), which was the first printed work on the subject of permanent artillery fortification. Dürer does not put forward a new system of fortification but presents a synthesis of contemporary ideas in Germany and Northern Italy. He had travelled to Italy in 1494 and 1505 but never got as far as Florence and Rome, where he would have seen the most advanced examples of military engineering. These included the development of the angle bastion, which was to dominate the art of fortifications for the next three centuries.
Dürer’s main contribution to the design of fortifications was his promotion of squat, semi-circular bastions. While his innovation was ignored in his native Nuremburg it bore fruit in England under Henry VIII when, between 1539 and 1543, he fortified the east coast of England. 1
Dürer’s woodcut representing the siege of a fortress features the rounded bastions described by Dürer in his publication. The defenders are seen about to counter-attack. Dürer’s woodcut was not part of the original publication but this was evidently the intention as the woodcut is described in a preparatory manuscript for Dürer’s book held in the British Museum. The bastion being attacked in the woodcut is closely related to the one described in the first part of Dürer’s treatise. The cross section allows us to understand the construction of gun platform, embrasures, parapets and “Streichwehren” (the low-level ventilated casemates that command the ditch and flanks of the bastion and which are only accessible via vaulted passages within the structure). Based on the evidence of a surviving drawing Dürer had been witness to a similar siege in 1519.
1Christopher Duffy. Siege warfare: the fortress in the early modern world, 1494-1660. (London: Routledge & Kegan Paul, 1979).