St Patrick is the patron saint or Ireland. He was a Christian missionary born in Britain. When he was 16 he was enslaved by Irish Raiders for 6 years before returning to his family when God spoke to him and told him it was his time to leave Ireland.
After his return home, he entered the catholic church and returned to Ireland as a missionary because God told him to do so in another vision. So he returned to start converting the Irish to Christianity. The Irish had pagan religions at that time and he incorporated their religious rituals into Christianity to get people to convert and eventually leave their pagan ways.
You know how Catholicism is something we associate with the Irish now, that all started with St. Patrick.

