Francesco di Giorgio Martini 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 later Quattrocento architects". As a military engineer, he executed architectural designs and sculptural projects and built almost seventy fortifications for the Federico da Montefeltro, Count of Urbino, building city walls 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.
He composed an architectural treatise Trattato di architettura, ingegneria e arte militare, the third of the Quattrocento, after Leone Battista Alberti's and Filarete's; he worked on it for decades and finished sometime after 1482; it circulated in manuscript.