Compléter Saint Patrick's DayVersion en ligne Saint Patrick's Day par Cynthia Mena 1 Catholics liturgical Franciscan feast obligation celebrated March Catholic holy Irish century Patrick's Saint Day ( Irish : Lá Fhéile Pádraig ) colloquially St . Paddy's Day or simply Paddy's Day , is an annual day that celebrates Saint Patrick ( circa AD 387 ? 493 ) , the most commonly recognised of the patron saints of Ireland , and is generally on 17 . St . Patrick's feast day was placed on the universal calendar in the Church due to the influence of the Waterford - born scholar Luke Wadding in the early part of the 17th , although the feast day was celebrated in the local church from a much earlier date . St . Patrick's Day is a day of for Roman in Ireland .