Saint Patrick's Day song

Saint Patrick’s Day is traditionally a day of dancing and feasting in honour of St Patrick.
Saint Patrick of Ireland is one of the world’s most popular saints. Along with Saint Nicholas and Saint Valentine, the secular world shares a love of these saints.
Among other things, Saint Patrick is known for driving the snakes out of Ireland. It is true that there are now no snakes in Ireland, but there probably never have been.
Since snakes represent evil in literature, the idea of Saint Patrick driving the snakes out of Ireland is symbolically saying he drove the old, evil, pagan ways out of Ireland.