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 . The funerary monument is set in a niche above the altar, with the recumbent effigy of a young man placed inside a mortuary chamber and flanked by two angels. The reliefs were carved by an Umbrian sculptor, probably of local origin. Between the tomb and the stained glass window appears a frescoed triptych attributed to Giotto's school, representing the Madonna and Child with Saint Francis and Nicholas . The cycle decorating the walls of the chapel, completed by 1307, comprises twelve scenes painted on the ceiling and on the walls illustrating the life and miracles of St Nicholas A scene of the chapel's dedication is painted above the arch of the entrance on the southern wall: the Redeemer receives the homage of Giovanni Orsini, presented by St. Nicholas, and of Napoleone Orsini, presented by Saint Francis. The stained glass windows show Cardinal Napoleone presented to Christ in the summit and his brother presented to Saint Nicholas in the zone below. At the southern end of the transept cardinal Orsini commissioned another chapel, dedicated to St John the Baptist, which was probably originally built for the tomb of Napoleone Orsini himself, but the cardinal was never buried there and the tomb remained empty . The parallel architectural arrangement of both Orsini chapels suggests that they were conceived together. However, the decorations of the chapel dedicated to Saint John the Baptist were never finished . Pietro Lorenzetti ( or his workshop) executed a frescoed triptych with a Madonna and Child with Saints John the Baptist and Francis.