Saint Patrick's Day, which takes place on March 17, commemorates the death of Ireland's patron saint. It was first celebrated as a religious feast around the ninth or 10th century.
Saint Patrick is believed to have died on March 17 in AD 461. Some years later, the pope canonized him as the patron saint of Ireland. Between 800 and 900, the Irish people began commemorating the day of his death. These celebrations were mostly religious feasts, but since it often took place during Lent, the church gave a reprieve for eating meat, drinking and dancing on that day.
The first Saint Patrick's Day parade was held on March 17, 1762. It was performed by Irish soldiers in the English army on the streets of New York City. The celebrations increased dramatically when Irish immigration to the United States exploded during Ireland's Great Potato Famine in 1845. Over 1 million Irish Catholic immigrants helped the holiday's popularity grow in the United States.
Up until the 1970s, Saint Patrick's Day had remained a minor holiday in Ireland with very little drinking, because the pubs were closed. America is credited with turning the holiday into the great party it is known for today.