The chapel at the right end of the transept is the church's greatest treasure. The chapel was inaugurated in 1493, and is also known as the Chapel of St Thomas Aquinas. The magnificent triumphal arch is attributed to Mino da Fiesole, Andrea del Verrocchio and Giuliano da Maiano. A pair of massive doubletted ribbed Corinthian pilasters support a pair of doubletted posts from which the semicircular archivolt springs.