This 12th-century church – Arezzo's oldest – has an exotic Romanesque arcaded facade adorned with carved columns, each individually decorated. Above the central doorway are 13th-century carved reliefs called Cyclo dei Mesi representing each month of the year. The plain interior's highlight – being restored at the RICERCA Restoration Studio at the time of research – is Pietro Lorenzetti's polyptych Madonna and Saints (1320–24). Below the altar is a 14th-century silver bust reliquary of the city's patron saint, San Donato.

　　Other treasures include a 13th-century crucifix by Margarito di Arezzo (left of the altar by the door to the sacristy) and a fresco on a column (across from the sacristy door) of Sts Francesco and Domenico by Andrea di Nerio (1331–69).