Francesco di Giorgio Martini (1439 šC 1501) was an Italian painter of the Sienese School and a sculptor, as well as being, in Nikolaus Pevsner's terms: one of the most interesting later Quattrocento architects and a visionary architectural theorist; 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, for whom he was working in the 1470s, building city walls as at Iesi and early examples of star-shaped fortifications.Born in Siena, he apprenticed as a painter with Vecchietta. In panels painted for cassoni he departed from the traditional representations of joyful wedding processions in frieze-like formulas to express visions of ideal, symmetrical, vast and all but empty urban spaces rendered in perspective.