Simplify the following text for a Grade 8 native English-speaking person.
Original: Saint Patrick 's Day is the feast day of Saint Patrick , the patron saint of Ireland and a day of celebration for Irish people and all things that are Irish .
Simplified: Saint Patrick 's feast day , as a kind of national day , was already being celebrated by the Irish in Europe in the ninth and tenth centuries . In later times he became more and more widely known as the patron of Ireland .