The museum is located in the Palace of the High Priest in the center of Chianciano. It was started as a Hall of Ancient Art in 1923 and was reorganized in 1988 according to modern museum criteria. It holds important religious paintings and objects from the 1300s-1800s and which belong to the parish, the Municipality and other churches in the area.
Especially important is a large crucifix from 1300 by Segna di Bonaventura, a Madonna on wood by the Nicola Pisano school, a beautiful polytich with the Madonna and the Saints of the Master of Chianciano. The icon showing San Giovanni Battista that holds up Chianciano from the 1500s reveals the way the town used to look.