Siena's cathedral is beyond question one of the finest Gothic churches in Italy. The multicolor marbles and painted decoration are typical of the Italian approach to Gothic architecture—lighter and much less austere than the French. The amazingly detailed facade has few rivals in the region. It was completed in two brief phases at the end of the 13th and 14th centuries. The statues and decorative work were designed by Nicola Pisano and his son Giovanni, although most of what we see today are copies, the originals having been removed to the nearby Museo dell'Opera Metropolitana. The gold mosaics are 18th-century restorations. The Campanile (no entry) is among central Italy's finest, the number of windows increasing with each level, a beautiful and ingenious way of reducing the weight of the structure as it climbs to the heavens.
The Duomo's interior, with its dark green–and–white striping throughout and illusionistically coffered and gilded dome, is simply striking. Step
in and look back up at a copy of Duccio's (circa 1255–1319) panels of stained glass that once filled the circular entrance window—the originals are now in the Museo dell'Opera Metropolitana. Finished in 1288, the window is the oldest example of stained glass in Italy. The Duomo is most famous for its unique and magnificent inlaid-marble floors, which took almost 200 years to complete; more than 40 artists contributed to the work, made up of 56 separate compositions depicting biblical scenes, allegories, religious symbols, and civic emblems. The floors are covered for most of the year for conservation purposes, but are unveiled during September and October. The Duomo's carousel pulpit, also much appreciated, was carved by Nicola Pisano (circa 1220–84) around 1265; the Life of Christ is depicted on the rostrum frieze. In striking contrast to all the Gothic decoration in the nave are the magnificent Renaissance frescoes in the Biblioteca Piccolomini, off the left aisle. Painted by Pinturicchio (circa 1454–1513) and completed in 1509, they depict events from the life of Aeneas Sylvius Piccolomini (1405–64), who became Pope Pius II in 1458. The frescoes are in excellent condition, and have a freshness rarely seen in work so old.
The Duomo is grand, but the medieval Sienese people had even bigger plans. They wanted to enlarge the building by using the existing church as a transept for a new church, with a new nave running toward the southeast, to make what would be the largest church in the world. But only the side wall and part of the new facade were completed when the Black Death struck in 1348, decimating Siena's population. The city fell into decline, funds dried up, and the plans were never carried out. (The dream of building the biggest church was actually doomed to failure from the start—subsequent attempts to get the project going revealed that the foundation was insufficient to bear the weight of the proposed structure.) The beginnings of the new nave, extending from the right side of the Duomo, were left unfinished, perhaps as a testament to unfulfilled dreams, and ultimately enclosed to house the adjacent Museo dell'Opera Metropolitana. The Cripta was discovered during routine preservation work on the church and has been opened to the public. The last entrance to the Duomo is 30 minutes before closing.