One of the most important monuments of the town and perhaps the most spectacular of the Amiata is located in the valley, just outside the village of Seggiano, surrounded by centuries-old olive trees: it is the splendid Sanctuary of the Madonna della Carità.
The construction of the Madonna della Carità is part of a precise historical-religious context: we are in the era of the Counter-Reformation and of the renewal and extension of the cult of the Virgin Mary. The spread of new forms of worship and Marian piety is particularly accentuated in the Tuscany of Ferdinando I, under whose reign (1587-1609) numerous churches and convents were built. The new development of popular religiosity and the construction of new churches are also connected to the disastrous famines that raged in Tuscany after 1590. All the most important churches built or enlarged in the Sienese area at the end of the 16th and beginning of the 17th century are dedicated to Madonnas considered miraculous. Also the Madonna della Carità di Seggiano, built between 1589 and 1603, fits into this climate of renewed religious fervor and development of the Marian cult: it was erected at the behest of the Bishop of Pienza Francesco Maria Piccolomini and the Sienese Ugurgieri family, with the contributions of the Community and with the alms of the people. Legend has it that the church was erected as thanks for the gift of a miraculous bread made from a sacred image in a period of famine to a mother who had invoked it. The peculiarities of the Seggianese church compared to other contemporary religious buildings are its links with schemes linked to the taste and Central European mannerist culture, which make it an exceptional case for the territory.
The church, which remains a very interesting monument on an architectural level, still preserving the original shapes and decorations, however, has its peculiarity in the variety of decorative and ornamental elements in trachyte, in its particular artistic character derived from the eclectic culture brought by the Lugano masters to whom the work is attributed. In a 1985 research Renato Zangheri assigns the authorship of the work to Giovanni della Valle di Lugano, one of the many stonecutters and master builders of the Canton of Ticino active in Seggiano in the second half of the sixteenth century. The façade, where the trachyte decorations contrast with the light background of the plaster, has two orders, Doric at the bottom and a composite upper part marked by an architrave with metopes and triglyphs. On the portal there is the fresco of an Annunciation inside a volute frame. The brick dome has four segments, the bell tower has a double sail. The interior, divided into three rather central aisles, is covered with barrel vaults in the central part and cross vaults in the side aisles. The six side altars in trachyte were commissioned by various members of the Ugurgeri family and kept paintings on canvas all stolen in the 1960s. In the main altar of the presbytery there is a fresco with the Madonna and child.