The patron of San Gemini is Saint Gemine, celebrated on 9 October in the cathedral dedicated to him, whose existence is documented from the 12th century, though the church is thought to be older still. Tradition holds that the saint — the monk Yemin in life — evangelised the area between the 7th and 8th centuries: son of the Syrian general Miliziano, who converted to Christianity together with his wife Balia, he was imprisoned for his faith but managed to escape by sea to Fano, from where he began a pilgrimage that led him to these lands.
In the days before the patron's feast, generally from the last Saturday of September to the second Sunday of October, the town holds the Giostra dell'Arme, its most popular event: a historical re-enactment that culminates in a mounted challenge between knights of the two districts into which San Gemini is divided, the Rocca and the Piazza.
