Main chapel of the Vatican Palace, dedicated to Our Lady of the Assumption and as large as a church. It was designed by de' Dolci under Sixtus IV (reigned 1471-84), hence its name. The series of famous frescoes on the left wall of events in the life of Moses and on the right side of the life of Christ were done by Boticelli, Cosimo, Rosselli, Ghirlandaio, Perugino, and Pinturicchio. The ceiling, which is considered Michelangelo's masterpiece and the most gigantic piece of painting in existence, was begun in 1508 and finished four years later. Between sections of painted simulated vaulting, Michelangelo painted scenes from Creation, the Expulsion from Eden, and the Flood. On the lower part of this created vaulting are the famous series of the seated Prophets and Sibyls. In 1508 Julius II persuaded Michelangelo to paint the ceiling of the Sistine Chapel. It was finished in 1512. Twenty-three years later he began The Last Judgment, the most comprehensive painted composition in the world. It was completed in 1541. The marble screens and the choir gallery in the chapel were designed and executed by Mino da Fiesole. The altar, which only the Pope may use, is inlaid with mother of pearl. The Sistine Chapel is the private chapel of the Pope and the place where the conclaves for papal elections take place.