The patron of Trevi is Saint Emilian, celebrated on 28 January in the cathedral dedicated to him. Not far away stands the olive tree of Sant'Emiliano, an age-old tree over 1700 years old.
On the evening of 27 January, the eve of the saint's feast, along a route unchanged for centuries, the nocturnal Illuminata procession takes place, one of the oldest events in Umbria. Trevi's calendar also keeps the memory, tied to an older episode, of a crucifix lowered from the cross and carried in procession every five years in the month of May, and every twenty-five years along a long route all the way to the main town.
