Geminianus was bishop of Modena in the fourth century — born at Cognento in 312, dead in the city in 397 — and is its patron. The cathedral, Lanfranco's Romanesque masterpiece, stands exactly on his tomb, and the relics lie in the crypt in a fourth-century urn resting on reused columns.
On 31 January that sarcophagus is opened: the remains, dressed in episcopal vestments with the crosier beside them, are exposed to the devotion of the faithful, and in the cathedral people may kiss the saint's arm, kept in an urn of the same shape.
The same day the city holds the Fiera di San Geminiano, two weeks after the Sant'Antonio fair of 17 January.