Initially, St. Patrick's Day was a solemn religious observance in Ireland, featuring church services and feasts in his honor. However, as Irish immigrants spread around the world, particularly to the United States, the holiday transformed into a broader celebration of Irish culture and heritage.

While St. Patrick’s Day festivities have strayed from their saintly origins, and are now marked by green-dyed food, parades and leprechauns, the holiday remains tied to St. Patrick and the first feast in his honor in 1631.