The figure of San Galgano left such a remarkable impression on his contemporaries that an oratory was built and dedicated to him on Montesiepi, the site of his hermitage, within the territories given to the Cistercian monks. The church was consecrated by Hildebrand Pannocchieschi, Bishop of Volterra, as early as 1185, the year of Galgano’s canonisation. The building was to contain the saint’s body and the sword embedded in the stone, the symbol of his abandonment of his life as a knight to follow his spiritual calling.

A few decades later, in 1218, the construction of the Cistercian abbey was begun. Together with the chapel of Montesiepi, this now represents the most important religious group in Tuscany. Leading the work was perhaps the same Johannes who had supervised the construction of the abbey of Casamari in Lazio. By 1262, the abbey was practically finished and it was consecrated in 1288. The Cistercian building acquired such social and economic importance that the Commune of Siena established relations with the monks. In 1257 one of them, Don Ugo, was given the appointment of “camerlengo”, that is, he was in charge of the Sienese treasury. Fra Melano is remembered for having stipulated the contract with Nicola Pisano in 1266 for the construction of the marble pulpit for Siena Cathedral. The plague of 1348 badly hit the community of monks, marking the beginning of a gradual decline. This culminated in 1474 when the monks decided to move to Siena, to the Palazzo known as San Galgano. In the following century, the church was stripped of its lead roof, and restoration work carried out in 1577 was much needed. Records show that the structure fell into further disrepair in subsequent decades, until two episodes irreversibly decided the fate of the abbey: in 1781 the remaining parts of the roof collapsed, and in 1786 the tower was struck by lightning and destroyed. In 1789 the abbey was deconsecrated and not long afterwards turned into a farm. Some restoration work carried out in the 19th century temporarily remedied the main damage, but a full-scale restoration operation was not begun until 1926. This aimed to strengthen, and therefore to preserve, what remained of the original structure. The fate of the Hermitage of Montesiepi is more fortunate. The church’s circular plan is reminiscent of the mausoleums of Roman origin. The external cladding alternates between a high stone footing and an area of two-coloured marble banding and bricks. It terminates in a wide ring of bricks only. A lantern was added to the roof in the 16th century and the bell gable is from the 14th century. The interior is particularly fascinating because of the structure’s simplicity and the boldness of some of its architectural solutions. The central dome, for example, alternates rows of white stone contrasting with the red of the bricks, as on the outside. The circular plan is interrupted only by an apse with a narrow lancet window. In the centre of the rotunda is the rock into which, according to tradition, San Galgano drove his sword. In 1340 a rectangular construction was added to the original building, set against its northern side. It features cross-vaulting, and is divided into four rooms. This new area was painted with frescoes with a cycle dedicated to the Life of the Virgin, carried out by Ambrogio Lorenzetti and his workshop. On the upper part of the central wall is a Majesty with Angels and Saints; at the foot of the scene is portrayed Eve lying down. In the lower part is the Annunciation.. During restoration work in 1966, the sinopie (or preparatory sketches) of these frescoes were uncovered, allowing for a deeper interpretation of the pictorial cycle. In the case of the Annunciation, there are some differences between the sketch and the actual fresco: in the sinopia the Virgin appears almost upset by the arrival of the Angel and embraces the column, as if to defend herself from the sudden apparition by turning her face. The whole cycle alludes strongly to the theme of maternity which seems to reappear in the figure of Eve with her prominent belly beneath her lightweight dress. The representation of the Majesty is connected to San Galgano’s vision of the Virgin with twelve apostles; in Ambrogio’s painting Peter, Paul, John the Baptist, and John the Evangelist appear; the other figures which replace the apostles of the vision are a pontiff (maybe Lucius III who canonised Galgano), and four monks, two of which are Cistercians. Ambrogio’s presence at Montesiepi, recorded in 1334, confirms the late dating of the work which was carried out in the last years of the artist’s activity, before he died; he was almost certainly a victim of the plague in 1348, and, in fact, no records of the painter exist after that year. This cylindrical church was built where the knight Galgano Guidotti, become a Cistercian monk, lived as an hermit till 1181, when he died. Is kept here the sword which, according to the tradition, Galgano drove into the rock to symbolise his renunciation to the worldly life. It was consacred in 1185. It has a small semicircular apse and a quadrilateral room used as pronaos; the covering consists in a hemispheric dome with alternated chromatic fascias. In the neighbour chapel, built at the beginning of the 14th century, there are frescoes by Ambrogio Lorenzetti, nowadays damaged, representing "Scenes of the life of Saint Galgano", a "Majesty" and an "Annunciation".