The architectural structure of the Oratory of St. Bernardino, originally erected in the later Middle Ages, was completely overhauled and renovated in the 16th century. This evocative setting, one of the most interesting museum spaces in Siena, which has housed the Diocesan Museum of Religious Art in its adjacent rooms since 1999, offers the visitor a comprehensive overview of Sienese painting from the 13th century onwards. The building, which was built to host the Confraternity of St. Mary and St. Francis, was rededicated in the 16th century to Brother Bernardino Albizzeschi, a Franciscan friar canonised in 1450 who frequently delivered fiery sermons in the square outside the building. The simple gabled brick façade is embellished with an elegant travertine portal dated 1574, above which we see St. Bernardino's symbol, a sun with twelve rays in whose centre stand the three letters IHS, an abbreviation for Iesus Homimun Salvator, Jesus the Saviour of Men. The core of the museum is still the very fine upper oratory chapel dedicated to St. Mary of the Angels which was frescoed throughout by Domenico Beccafumi, Giovanni Antonio Bazzi known as "Il Sodoma” and Girolamo Pacchia in the early 16th century.