St. Patrick is the patron saint of Ireland,
although he was born in Britain.
Many miracles have been attributed to the bishop, including the driving of the snakes from Ireland.
His sainthood derives from his conversion of the Irish celtic pagans to Christianity.
He used the native shamrock as a symbol of the holy trinity
when preaching and brought the Latin alphabet to Ireland.
March 17 is the feast day of St. Patrick, of course.
St. Patrick's Day was first celebrated in America
in Boston, Massachusetts in 1737,
and is now celebrated nationwide as an opportunity to wear green and consume green libations.
The celebration in Ireland is more of a religious matter,
whereas in the U.S., it's a festive occasion.
The wearing o' the green is a symbol of Ireland's lush green farmlands.