7 facts about St. Patrick 's DayOriginally a religious holiday to honor St. Patrick St. Patrick 's Day has evolved into a celebration of all things Irish .
St. Patrick introduced Christianity to Ireland in the fifth century .
7 facts about St. Patrick 's DayOriginally a religious holiday to honor St. Patrick , who introduced Christianity to Ireland in the fifth century , St. Patrick 's Day has evolved into a celebration of all things Irish .