Secundinus, or Sechnall as he was known in Irish, was founder and patron saint of Domhnach Sechnaill, County Meath, who went down in medieval tradition as a disciple of St Patrick and one of the first bishops of Armagh. Historians have suggested, however, that the connection with St Patrick was a later tradition invented by Armagh historians in favour of their patron saint and that Secundinus is more likely to have been a separate missionary, possibly a companion of Palladius.

The Archbishop of Armagh is an archiepiscopal title which takes its name from the city of Armagh in Northern Ireland. Since the Reformation, there have been parallel apostolic successions to the title: one in the Roman Catholic Church and the other in the Church of Ireland. The archbishop of each denomination also holds the title of Primate of All Ireland.