ABSTRACT
The invention of the angular bastion is a significant moment in the history of design, when visual thinking, an alliance between painting, architecture and psychology of invention, lead to the creation of a new urban type. As J. R. Hale (1965) stated, it was the most original of all architectural forms invented in the Renaissance. Giorgio Vasari wrote about it in Le Vite, crediting Michele Sanmicheli with having introduced it in his project for the Cornaro and S. Croce sections of the fortification of Padua. Vasari wrote that its angular configuration is superior to the round one. Most historians since, agreeing with Vasari’s attribution to Michele or not, have continued to discuss the development of fortifications in the same terms, as a transition from the round to the angular bastion, limiting their search to the problem of who conceived it first and when. Fewer historians have tried to justify Hale’s claim and explain the significance of this invention. Even fewer have tried to explain how this new important conception came about, and those who have usually invoke technological reasons, in particular the appearance of the cannon.
