March 17 1762 in New York City the world’s first St. Patrick’s Day parade is held by Irish soldiers serving in the British army in honor of the patron saint of Ireland. They are celebrating the Saint, born in the late 5th century, who converted almost all of Ireland to Roman Catholicism. As Irish immigration to America increases, so the parade becomes more widespread and festive. Today, millions of Americans of Irish ancestry—and plenty of “Irish-for-the-day” folks—celebrate Irish cultural identity and history by enjoying and parades and engaging in general revelry.