 In the Irish Civil War which followed Lemass was adjutant and second in command to Rory O'Connor, when the group seized the Four Courts, the home of the High Court of Ireland.The occupation of the Four Courts eventually resulted in the outbreak of Civil War, when, under British pressure, the Free State side shelled the building on 28 June 1922.As a result, fighting broke out in Dublin between pro and anti Treaty factions.