Saint Fermin of Amiens (also Firmin, from Latin, Firminus; in Spanish, Fermín; in Basque, Fermin) is one of many locally venerated Catholic saints. Fermin is the co-patron of Navarre, where his feast, the 'San Fermín' in the capital Pamplona, is forever associated with the Encierro or 'Running of the Bulls' made famous by Ernest Hemingway. Fermin was long venerated also at Amiens, where he met martyrdom.

Fermin is said to have been the son of a Roman of senatorial rank in Pamplona in the 3rd century, who was converted to Christianity by Saint Honestus, a disciple of Saint Saturninus. According to tradition, he was baptised by Saturninus (in Navarra "San Cernin") at the spot now known as the Pocico de San Cernin, the "Small Well of San Cernin", across from the facade of the church dedicated to St Cernin, which is built on the foundations of a pagan temple.

Saturninus (in France "Saint Saturnin") was the first bishop of Toulouse, where he was sent during the "consulate of Decius and Gratus" (AD 250). He was martyred (traditionally in 257 AD), significantly by being tied to a bull by his feet and dragged to his death, a martyrdom that is sometimes transferred to Fermin and relocated at Pamplona. In Toulouse, the earliest church dedicated to Notre-Dame du Taur ("Our Lady of the Bull") still exists, though rebuilt; though the 11th century Basilica of Saint Sernin, the largest surviving Romanesque structure in France, has superseded it, the church is said to be built where the bull stopped, but more credibly must in fact be on a site previously dedicated to a pre-Christian sacred bull, perhaps the bull of Mithras. The street, which runs straight from the Capitole, is named, not the Rue de Notre-Dame, but the Rue du Taur.