Onesimus of Soissons was a 4th-century bishop who served several regions in France, including Soissons, Laon, and Saint-Quentin. Appointed to his position around 350 AD, he acted as the fifth bishop of the Soissons see. He remained in this ecclesiastical office until his death in 361 AD. Recognized as a saint within the Catholic tradition, his life and leadership occurred during the pre-schism era of the early Church.