A marble loggia at the base of the tower where it meets the Piazza del Campo, known as the "Cappella di Piazza", was added in 1352 to fulfil a vow to the Holy Virgin by Sienese survivors of the Black Death. The corner pilasters attained their current form in 1378, the sculptures decorating them being executed in 1378-1382 by Mariano d'Angelo Romanelli e Bartolomeo di Tommé. The simple wooden ceiling once covering the loggia was replaced by the current Renaissance marble vault in 1461-1468 by Antonio Federighi, also author of the bizarre decorations of the coronation. In 1537-1539 Il Sodoma painted a fresco above the altar, now housed in the town museum in the Palazzo Pubblico.