Michelangelo inherited the project to design the dome of St. Peter's basilica in 1546. It had previously been in the hands of Bramante (with Giuliano da Sangallo and Fra Giovanni Giocondo) until 1514, Raphael Sanzio (assisted by Giuliano da Sangallo and Fra Giovanni Giocondo) until 1520, and Antonio da Sangallo the Younger (with Baldassare Peruzzi), whose work was disrupted by the sack of Rome in 1527. The design had been altered by Giuliano da Sangallo from being hemispherical to being 9 meters taller, segmental, and ribbed, and he had strengthened the piers and completed building the pendentives.