This is the traditional feast day of San Filippo Benizi, patron saint of the thermal springs of Bagni San Filippo. Florentine by birth, he joined the order of the Servants of Mary and even became their Superior General, but retreated to the Bagni in 1269 in order to lead the life of a hermit and escape from the designs of the cardinals at the stormy Conclave of Viterbo, who wanted to elect him to the pontifical seat. The religious progamme of the festival opens on 22 August with a procession of the faithful from the local church to a grotto where, according to tradition, the saint lived for a certain period of time. On the 23, the exact feast day, the parish priest celebrates two Holy Masses: one at 9am in the church, and one at 11am in the grotto, along the so-called 'chestnut' road (stada 'dei castagni'), which leads to Campiglia. The festival programme also includes sporting and gastronomic events.