The interior of this church (1282-1324) was modified in the 19C and as a result has lost most of its original decor. In the right-hand side aisle, the splendid Cappella Brancaccio was painted by Pietro Cavallini (1309). Behind a balustrade, the upper portion of the 18C wainscoted sacristy houses 42 coffins of prominent figures from the court of Aragon.