Dáil Eireann approves the Anglo-Irish Treaty; de Valera and his supporters leave Dáil Eireann; the Irish Free State Act is passed; Rory O'Connor's anti-treaty IRA occupies the Four Courts; the Irish Civil War begins; Arthur Griffith dies and Michael Collins is assassinated; Kilkenny are the 1922 hurling champions, Dublin are the 1922 football champions, King's County and Queen's County change their names to Offaly and Laois respectively.