Some frescoes, made by brothers Pietro and Ambrogio Lorenzetti around the 1330s, adorn the transept. The fragments are part of a cycle of frescoes devised for the chapter house and the friary cloister, and were detached from their place of origin and moved to the Basilica in 1857. The third chapel to the left of the altar houses a Crucifixion by Pietro, framed by a nineteenth-century motif. The . . .