Which Irish saint was sent to Ireland before Saint Patrick?

Saint Palladius was the Irish saint sent to Ireland before Saint Patrick.

Prosper of Aquitaine records that Pope Celestine I ordained Palladius and sent him in 431 as the first bishop to Christians among the Irish, described in Latin as the Scotti believing in Christ. This wording suggests that Christian communities already existed in Ireland before either mission became central to later tradition.

Palladius’s work appears to have focused mainly on eastern and southern Ireland, especially Leinster. Later Irish accounts say that he preached there but was opposed by the king of Leinster and eventually left for Britain. Some traditions connect him with places such as Clonard and with other early missionaries.

Palladius is sometimes confused with Patrick because later writers blended their stories, and Palladius may have been known by the name Patricius. That confusion helped make Patrick appear to be Ireland’s sole early missionary. Historically, Palladius’s documented mission came first, in 431, one year before the traditional date for Patrick’s arrival.