May 20, 685Battle of Dunnichen, the Picts Stopped the Advance Northwards of the Angles of Northumbria
May 20, 1311The War of the O'Briens of Thomond Escalates as the Norman-Irish Become Involved on Both Sides
May 20, 1747James Lind Began a Controlled Experiment Which Demonstrated That Citrus Fruits Could Prevent Scurvy
May 20, 1836An Act Amalgamates the County Constabulary and Peace Preservation Force Into a Centralized Police Force, the Irish Constabulary
May 20, 1932Amelia Earhart Takes Off From Newfoundland for Ireland on the Anniversary of Charles Lindberghs Famous