The church of San Francesco was where St. Bernardino first donned his monkish robes. The exact spot where he prayed and began preaching is now marked by the Oratory of San Bernardino, built in the late 15th century. The lower of the oratory's two levels was frescoed by the best 17th-century Sienese artists -- including Francesco Vanni, Rutilio and Domenico Manetti, and Ventura Salimbeni -- and houses a little Madonna by Sano di Pietro. The upper level has higher-quality frescoes depicting the Life of the Virgin by 16th-century artists Sodoma, Domenico Beccafumi, and Girolamo del Pacchia. The rooms that make up the Diocesan Museum contain minor panel paintings (including a couple by Matteo di Giovanni) and detached fresco fragments.

Via del Comune doglegs off Via dei Rossi just down from Piazza San Francesco and leads to the 14th-century double city gate Porta Ovile, which preserves a tabernacle frescoed by Sano di Pietro. Just outside the gate you'll find the 1262 Fonte Ovile, one of the city's most picturesque public fountains.