This Chapel of Saint Nicholas of Bari , at the northern end of the transept , was commissioned by the papal legate Cardinal Napoleone Orsini .
Chapel contains the tomb of the cardinal 's brother , Giovanni Orsini , who died between 1292 and 1294 .
This Chapel of Saint Nicholas of Bari , at the northern end of the transept , was commissioned by the papal legate Cardinal Napoleone Orsini and it contains the tomb of the cardinal 's brother , Giovanni Orsini , who died between 1292 and 1294 .