The legend is that St. Patrick drove all the snakes out of Ireland. I guess they all ended up selling credit default swaps or pushing religion on TV once they left the Emerald Isle.
Whatever your heritage, enjoy the day. It’s a national holiday in Ireland, of course, and also in Montserrat, the lush little island in the Caribbean that was settled by Irish sugar farmers in the 17th century. Erin go bragh, mon.