Nicasius of Rouen

Saint Nicasius of Rouen, hieromartyr, called the Apostle of the Vexin, was a saint and martyr in Gaul in the third century. He is sometimes considered the first bishop of Rouen. The Church commemorates him on 11 October, and the Roman Martyrology also has him on that day. In art he is shown carrying his head in his hands, after the manner of his martyrdom, and also as a bishop.

The Liber Eburneus of the cathedral of Rouen shows Saint Mellon as first bishop of Rouen, but the Liber Niger of Saint Ouen and the episcopal lists from the twelfth century mention the episcopate of a certain Nicasius as earlier than that of Mellon. As to the year of his death, one source says it was perhaps about 260, while another says only that he lived in the third century.

According to tradition, Nicasius was an associate of Denis of Paris. From confusion of this Denis with Dionysius the Areopagite, some supposed that Nicasius was born in Athens. According to Hilduin of Saint-⁠Denis, Nicasius evangelized the Vexin. He spent a year at Mousseaux and evangelized Rolleboise nearby. He worked several miracles and evangelized numerous places along the Seine, among them Conflans, Andrésy, Triel, Vaux, Meulan, Mantes and La Roche-⁠Guyon. His companion, Quirinus, is said to have delivered the people of Pontoise from a dragon.

Nicasius and his two companions were beheaded on the banks of the Epte at Gasny, before reaching Rouen. He was believed to have been buried at Gasny. At the beginning of the ninth century the relics of Quirinus were moved to Malmedy Abbey. Saint Mellon, probably his successor in the see, is traditionally said to have been a disciple of Nicasius. The Russian source names his companions as Quirinus and Scuviculus.