History and legend intertwine to create the story of St. Patrick. The only definite statement that can be made about St. Patrick's life is that he was not Irish. As far as anyone has been able to determine, St. Patrick was a Britannic Celt who was reared as a Roman Catholic. It is not known whether March 17 was the birth or death date of St. Patrick; it may be neither.

St. Patrick is best known for driving the snakes out of Ireland. The snake was a pagan symbol, so this Irish folk tale may allude to St. Patrick driving paganism out of Ireland.

The first American St. Patrick’s Day celebration appears to have been in Boston in 1737. The custom was begun by the Charitable Irish Society of Boston, a Protestant organization founded that year to help needy Irishmen.

The shamrock as a symbol of St. Patrick’s Day recognizes the saint’s use of the clover to explain the Christian concept of the Trinity – the three leaves representing the Father, Son and Holy Spirit, with the stem representing the Godhead.

Over time, the rich traditions of the Irish have been embraced as part of the U.S. cultural heritage, and while it remains a festive holiday, St. Patrick’s Day has become an occasion to honor and celebrate the Irish culture.

Hallmark St. Patrick’s Day card sales are highest in the Northeast, with New York City being the top city.

Industry-wide, Americans exchange about 9 million St. Patrick’s Day cards annually.