He became a saint after his death, because he brought Christianity to Ireland.
Nobody. St. Patrick's Day did not begin until years after St. Patrick was already dead. If he celebrated the day, he was already in heaven.
short and sweet..... a saint. for more info go to http://en.wikipedia.org/wiki/Saint_Patrick
St. Patrick was a bishop and missionary to Ireland.
In the 5th century there was a man named St.Patrick who brought Christianity to Ireland.