The bell tower of Santa Maria del Fiore was begun by Giotto in 1334, carried on after his death by Andrea Pisano, and finished in 1359 by Francesco Talenti, who created the large windows at the upper levels. The sculptural decoration of the tower is extremely rich: 56 relief carvings in two registers, and 16 life-size statues in the niches, all by Florentine masters of the l4th and l5th century (among whom Andrea Pisano, Donatello, Luca Della Robbia).

On the tower facade looking toward the Baptistery, the reliefs in the lower row depict the creation of man and woman, the beginnings of human work, and the "inventors" (according to the Bible) of various creative activities: sheep-herding, music, metallurgy, wine-making. In the upper register are the 7 planets, beginning with Jupiter at the north corner.

On the other facades, in the lower register we find astrology, building, medicine, weaving and other technical and scientific endeavors. In the upper registers are: on the south, the theological and cardinal virtues; on the east, the liberal arts of the Trivium and Quadrivium; to the north, the seven sacraments.

The statues in the niches represent the patriarchs, prophets and kings of Israel, and pagan sybils. The originals of all these works are in the Museum of the Opera