SANT'ANTIMO. - Ancient abbey 8 km from the diocese of Montcalmo, in the small valley of the Starcia stream, a tributary of the Orcia river.
The origins of the monastery date back to the time of Charlemagne, who founded it in thanksgiving to God for the cessation of the plague that was decimating his army in the Val d'Orcia. It was furnished with relics of Sts. Antimus and Sebastian, which Charles had obtained from Pope Adrian I. In the very year of Charlemagne's death, 814, his son Louis the Pious, by a diploma issued at Aachen, granted the abbey of S. Antimo and its territory in fief to the abbot of Montcalmo. The original church is the one now serving as a sacristy, a small one-aisled oratory with an apse behind the altar. The right-hand wall has monochrome frescoes depicting scenes from the life of St. Benedict, attributed to Giovanni d'Asciano (14th century). Beneath the little church is the crypt, accessible from the outside, with vaults supported by four small columns that divide it into three aisles. The present large church (44 m x 16 m) was built in the first two decades of the 12th century and is certainly one of the most beautiful and characteristic Romanesque churches in Italy, especially since it has undergone no alterations or mutilations and may be said to be intact, particularly in its interior. It is entirely of stone, even internally, with three aisles, the central one covered with beams, the side aisles vaulted, with a matroneum, an ambulatory behind the altar, and radiating chapels—a feature characteristic of Burgundian architecture and perhaps imported by monks from France. On the high altar is a seated Madonna with the Child, a polychrome wooden sculpture of the 13th century; on the façade wall, to the left, is a large wooden crucifix, also of the 13th century. In the small crypt beneath the high altar, a 6th-century funerary slab serves as the altar mensa. On the exterior, the walls of the side aisles today lack the blind arcades that once ran along the remaining half-columns; this deficiency is almost certainly due to the collapse of the upper part of the walls themselves (later rebuilt with ordinary masonry) under the pressure of the vaults of the matroneum. Even the simple façade originally had, in its lower part, four arches: two blind; in the two central ones opened a double door, later replaced, perhaps in the early 1200s, by the single portal now visible. The beautiful Romanesque bell tower is somewhat later than the church: one of the bells bears the date 1219. Of the monastery, only a few remains survive, among which noteworthy, on the ground floor, is a triforium flanked by an arched door that opened into the cloister; it may have provided light to the chapter house.
As mentioned, the abbots of S. Antimo exercised civil jurisdiction over Montcalmo as well, a right lost during the 13th century in conflicts with Siena; they exercised purely ecclesiastical jurisdiction over many monasteries and churches in the Sienese, Grossetan, Aretine, and Pisan territories. The abbey was suppressed in 1462 by Pius II because the number of monks had become too small, discipline had grown lax, and the patrimony had been squandered. The remaining assets were assigned to the mensa of the bishop of Montalcino.