On the right side of the transept is the tombstone of Don Pietro de Sabello (1288), a deacon. The figure is in priestly robes, with a stole; the hands crossed; he wears a biretta. The Savelli arms on either side of the figure. There is a border of very coarse opus Alexandrinum, mere rude fragments set in cement, with Gothic letters. His family had a fortress on the Aventine.