Sylvester

Saint Sylvester is remembered as a companion of Palladius on his mission to Ireland, and he died around the year 420. According to Wikipedia, Palladius was the first bishop of the Christians of Ireland, before Saint Patrick, a deacon of a prominent family of Gaul, consecrated bishop by Pope Celestine I and sent to Ireland. The sources at hand give no further details of Sylvester himself. He is venerated as a saint of the undivided Church and is commemorated on 10 March (new calendar).