The Collegiate Church is an iconic monument of San Quirico d’Orcia.
The present Collegiate Church, was an ancient parish church, preceded by an 8th-century baptistery.
Its present architectural appearance can be traced back to the 1200s-300s. The facade, ornamented with small arches and with a rose window of Gothic character, is dominated by the 12th-century Romanesque portal, preceded by a prothyrum, and with the arch set on columns knotted on two lionesses. The midday portal is attributed to Giovanni Pisano, one of the most influential artists of the 14th century.
Carved into the portal lintel is a bas-relief depicting a fight between two monstrous figures.
On the right side are two mullioned windows and another portal, with Lombard influences, surmounted by a cusped prothyrum supported by two caryatids resting on as many lions, attributable to the second half of the 13th century.
The interior is Latin cross with wooden truss roofing in the nave and with cross vaults in the transept arms. The bell tower is of later construction.