San Domenico is a 15th-century Gothic church just inside the southern wall of the old town, on a quiet stretch of Via Berrettini. The interior contains a 1402 polyptych by Lorenzo di Niccolò and a Madonna and Child by Fra Angelico's workshop, both of which would be highlights of a larger museum.
The church is rarely crowded — most visitors stop at San Francesco and skip this one. A worthwhile detour for anyone interested in early Renaissance painting.