The cathedral itself was originally designed and completed between 1215 and 1263.

Black and white are the colours of the civic coat of arms of Siena. 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).