Originally, the color associated with St. Patrick was actually blue. Over the years the color green and its association with St. Patrick’s Day grew. Green ribbons and shamrocks were worn in celebration of St. Patrick’s Day as early as the 17th century.
In 1903, Saint Patrick’s Day became an official public holiday in Ireland. This was thanks to the Bank Holiday (Ireland) Act 1903, an act of the United Kingdom Parliament introduced by Irish Member of Parliament James O’Mara.