Federico da Montefeltro
Francesco di Giorgio Martini (1439–1501) was an Italian architect, engineer, painter, sculptor, and writer. As a painter, he belonged to the Sienese School. He was considered a visionary architectural theorist—in Nikolaus Pevsner's terms: "one of the most interesting ". As a military engineer, he executed architectural designs and sculptural projects and built almost seventy fortifications for the Federico da Montefeltro, Count (later Duke) of Urbino, building city walls and early examples of star-shaped fortifications.