This admirable Romanesque-Gothic collegiate church was built in the 12C-13C. The elegant but simple façade features a magnificent Romanesque portal over which is a rose window. Note the two Gothic portals on the right-hand side of the church and inside, in the left transept, the reredos painted by Sano di Pietro. In addition, there is the recumbent statue of Count Henry of Nassau, who died in San Quirico in 1451 on his return journey from Rome.