The chapel is dedicated to SS Francis of Assisi and Giacinta Mariscotti. The latter was a nun of the family who patronized this chapel, hence the dedication. The interior was originally designed and decorated by Simon Vouet, a disciple of Caravaggio, in 1624. The frescoes on either side of the altar are by Francesco Manno (1807) showing St. Peter and St. Paul. Below the frescoes are bronze bas-relief sculptures showing their respective martyrdom.