Santa Maria a Castello, Romanesque church in Monteriggioni, Italy.

Santa Maria a Castello is a church in Monteriggioni whose original basilical layout had three naves with wooden roof and three apses; today only the central nave and part of the tribune remain. The façade is now a simple gabled wall with a late-medieval portal and an oculus, and the south flank preserves five stone arches on square pillars. The proto-Romanesque tribune has walls of river pebbles and rough stone, and the central apse is articulated by pilasters supporting two hanging arches.

Written records of this church first appear in 971, marking the beginning of its long history in the region. It evolved over centuries as an important religious presence in Tuscany.

The name Castello refers to the lost castle of Monteriggioni, and the church was the seat of a pieve, a baptismal church with jurisdiction over 33 suffragan churches in the 12th century. In 1401 its baptismal font was moved to the abbey of Isola, after which the ancient baptistery next to the church fell into disuse. The church is now part of an agriturismo and is not freely accessible.

The church is located within an agricultural tourism complex and has restricted public access. You should arrange a visit in advance to confirm when you can enter.

The ancient baptistery next to the pieve, dedicated to San Giovanni, fell out of use after 1401, when its font was moved to the abbey of Isola. The church itself lost its priests in the mid-14th century, after plague and war, and the population turned to that abbey for services.