This splendid building is on of the most beautiful Italian Cathedrals built in the Romanesque-Gothic style. The fa?ade is the finest part of the building, thanks to the graceful, the imposing marble walls enlivened with alternate pink and black stripes or rather dark and green and the nice mosaics.
Portal and arches are decorated with little columns. Spirals, flowers, cherubs etc. Carvings are in the lunettes. The fa?ade is also decorated with statues and ornaments, culminating in the great frame into which the rose window is inserted. The Busts of Thirty-six Patriarchs and Prophets are placed in little niches all around, on the top is the Holy Virgin and in the triangular sectors the Four Evangelists.
The sides are covered with alternate black and white stripes. On the left side is the palace of the Archbishop, on the right side are the walls of the unfinished New Cathedral. The four very fine blind double window in the wall of the right aisle are the faithful reproduction of those of The Abbey of San Galgano; The double windows in the nave are also to be admired. The cupola has hexagonal shape and it is covered with ribbed tiles and is surmounted with a polygonal lantern.
The interior is grandiose and austere, dominated by the rhythm of the arches resting on bi-colored columns. The Church is about 90 meters long and 25 meters wide. The style is Romanesque, though not without some touches of Gothic; the shape is that a Latin cross with one nave, two aisles, a transept, apse and dome.
The nave is separated from the aisles by two rows of five different styled pillars; the pillars continue in the cross and reach the final vault; they are twenty-six all in black and white horizontal marble stripes in equal succession cover the pillars in the nave, as well as in the transept and in the head of cross. The vaults over the transept are ribbed and painted blue with golden stars.
Close to the transept stands the finest piece of sculpture work treasured in the Cathedral ; the marble pulpit made by Nicola Pisano.
It contains also works by Gian Lorenzo Bernini ( 1608- 1680) the greatest Italian sculptor of the Baroque age.