In 1547 Michelangelo Buonarroti (1475–1564) took over the basilica project. Although he was seventy-two, he was still the most famous artist in Italy. Under his direction, construction of the dome finally began. Michelangelo built the dome’s base, called the drum. It was 65 feet (20 m) tall and 600 feet (183 m) in diameter. He surrounded the drum with sixteen columns. After Michelangelo’s death, Giacomo della Porta (ca. 1533–1602) took over the basilica project. He, too, focused his work on the dome. He changed the shape slightly and created a new construction plan. Workers spent twenty-two months raising the dome. It was finished on May 14, 1590. The dome rises 448 feet (137 m) above the floor of the basilica. Della Porta added a lantern (a small round tower) at the peak of the dome. In 1593 a copper ball and bronze cross were added to the lantern. The ball is 8 feet (2.4 m) in diameter and weighs 5,493 pounds (2,492 kilograms). The cross is 16 feet (5 m) tall. In 1608 the last of the old basilica was torn down. This made room for the new basilica’s nave and facade (front). The new architect, Carlo Moderno, decided to use the Latin cross (a cross shaped like a t, with one bar longer than the other) as the layout of the basilica. With a Latin cross design, the nave would be longer and would hold larger crowds. When finished, the nave measured 613 feet (187 m) long, 84 feet (26 m) wide, and 152 feet (46 m) high.