Introduction to St. Patrick's Day: March 17th every year is St. Patrick`s Day in Ireland to commemorate the patron saint of Ireland, St. Patrick. This festival originated in the late 5th century, with green and clover as its iconic elements. Every street and alley will be crowded with people. During the week before and after the festival, there will be street musical theater, carnival, dance, and comedy. , parades, etc., has now become Ireland's national holiday.