Francesco di Giorgio Martini was an Italian painter and sculptor of the Sienese school. He is also known as a visionary architectural theorist. As a painter he was apprenticed to Vecchietta. He was initially active in Orvieto and worked in Siena from 1463. In 1490 he was awarded the commission to design the model for the cupola of Milan's cathedral. His compositions show an interest in mechanical elements and depict such things as gear wheels. His sheer versatility gave significance to his artworks. He is perhaps best known for designing Santa Maria delle Grazie al Calcinaio in Cortona (built between 1485 and 1515).