The cathedral was begun at the end of the 13th century by Arnolfo di Cambio, and the dome, which dominates the exterior, was added in the 15th century on a design of Filippo Brunelleschi.

The exterior is notable for the geometric patterning of its revetment (face), made from encrusted marble. It mimics the Tuscan Romanesque style of the revetment on the baptistery.