Siena Cathedral - Interior

Interior

In the interior the pictorial effect of the black and white marble stripes on the walls and columns strikes the eye. Black and white are the colours of the civic coat of arms of Siena. The capitals of the columns in the west bays of the nave are sculpted with allegorical busts and animals. The horizontal moulding around the nave and the presbytery contains 172 plaster busts of popes dating from the 15th and 16th centuries starting with St. Peter and ending with Lucius III. The spandrels of the round arches below this cornice exhibit the busts of 36 emperors. The vaulted roof is decorated in blue with golden stars, replacing frescoes on the ceiling, while the formerets (half ribs) and the tiercerons (secondary ribs) are adorned with richly elaborated motifs.

The stained-glass round window in the choir was made in 1288 to the designs of Duccio. It is one of the earliest remaining examples of Italian stained glass. The round stained-glass window in the façade dates from 1549 and represents the Last Supper. It is the work of Pastorino de' Pastorini.

The hexagonal dome is topped with Bernini's gilded lantern, like a golden sun. The trompe l'oeil coffers were painted in blue with golden stars in the late 15th century. The colonnade in the drum is adorned with images and statues of 42 patriarchs and prophets, painted in 1481 by Guidoccio Cozzarelli and Benvenuto di Giovanni. The eight stucco statues in the spandrels beneath the dome were sculpted in 1490 by Ventura di Giuliano and Bastiano di Francesco. Originally they were polychromed, but later, in 1704, gilded.

Next to the first two pillars there are two fonts, carved by Antonio Federighi in 1462-1463. His basin for the Blessing of Holy Water was later transferred to the chapel of San Giovanni.

The marble high altar of the presbytery was built in 1532 by Baldassarre Peruzzi. The enormous bronze ciborium is the work of Vecchietta (1467–1472, originally commissioned for the church of the Hospital of Santa Maria della Scala, across the square, and brought to the cathedral in 1506). At the sides of the high altar the uppermost angels are masterpieces by Francesco di Giorgio Martini (1439–1502).

Against the pillars of the presbytery there are eight candelabras in the form of angels by Domenico Beccafumi (1548–1550), He also painted the frescoes, representing Saints and Paradise, on the walls in the apse. These were partially repainted in 1912. Behind the main altar is a very large painting Assumption of the Virgin by Bartolomeo Cesi in 1594. The presbytery keeps also the beautiful wooden choir stalls, made between 1363–1397 and extended in the 16c. Originally there were more than ninety choir stalls, arranged in double rows. The remaining 36 stalls are each crowned by the bust of a saint in a pointed niche. Their backs are decorated with carved panels, the work of Fra’ Giovanni da Verona in 1503.