ANTONIO DA SANGALLO (the Younger) courtyard of the Palazzo Farnese, Rome, 1517-1546. 3rd story and attic by MICHELANGELO. 1546-1550. Design of the project was awarded to Antonio da Sangallo the Younger. Work began in 1514, but when the original architect died in 1546, Michelangelo was called in. He designed the first two floors, built the third, and adorned the façade with a central balcony.