The most popular legend of St. Patrick, which is frequently told to children, states that St. Patrick drove all of the snakes out of Ireland. This is often considered an origin myth to explain why there are no snakes in Ireland.
The popular story of St. Patrick and the snakes is also considered to be symbolic of the Saint's efforts to convert pagans to Catholicism. However, there were no snakes in Ireland during St. Patrick's lifetime, according to National Geographic. According to scientists, an ice age more than 10 thousand years ago is the cause of the lack of snakes in Ireland, Iceland, Greenland and other large islands.