The most significant frescoes have been attributed to the so-called Master of Sestino, an artist active between the end of the fifteenth century and the beginning of the sixteenth century. In particular, the frescoes behind the main altar, which must once have extended over the entire wall, have been recovered. This pictorial cycle, dating back to the second half of the fifteenth century, depicts a Madonna and Child flanked by musician angels. Among the figures, a beautiful St. Sebastian stands out, almost perfectly preserved, and a Camaldolese monk saint who, in a singular way, keeps a miraculously tamed wolf on a leash. Camaldolese monk saint who, in a singular way, keeps a miraculously tamed wolf on a leash.