In the historic premises of the former convent of Sant'Agostino, you'll find the Civic and Diocesan Museum, one of the most important museums of medieval and modern art in the province of Siena. The collection can be accessed through one of the cloisters and features numerous styles, offering an interesting overview of Montalcino's artistic production.
Here, you can admire wooden works by Giovanni Pisano, Giovanni d’Agostino and Francesco di Valdambrino, as well as a Crucifix by Giambologna, paintings with gold backgrounds from the Sienese school, vestments and sacred jewellery from the 15th and 16th centuries, and archaic majolica drinking vessels. Among the most valuable pieces preserved in the museum rooms are two illuminated volumes of the Atlantic Bible dating back to the 12th century from the Abbey of Sant'Antimo.
Many of the works on display document the notable influence of Duccio di Buoninsegna, who was preminent in respect to the styles of others such as Simone Martini and the Lorenzetti brothers.
A small Renaissance gem is the Tamagni writing desk, painted inside the historic hospital of Santa Maria della Croce, now the Town Hall. Vincenzo Tamagni was a student of Raphael at the Vatican and frescoed the writing room in the early 16th century. On the walls, it's possible to admire women and men that represent models of virtue, as well as cartouches and inkwells made in trompe l'oeil, a reminder of its function.