This admirable Romanesque-Gothic collegiate church was built in the 12C-13C. The elegant but simple façade features a beautiful sculpted rose window with a magnificent Romanesque doorway projecting below. Note the two Gothic doorways on the right-hand side of the church and inside, in the left transept, the altarpiece painted by Sano di Pietro. Also of interest is the recumbent statue of Count Henry of Nassau, who died in San Quirico in 1451 on his return journey from Rome.