Irish War of Independence Irish nationalists, who were certain the men had been tortured then murdered. This day became known as Bloody Sunday. On 28 November 1920, only a week after Bloody Sunday in Dublin, the west Cork unit of the IRA, under Tom Barry, ambushed a patrol of Auxiliaries at Kilmichael in County Cork, killing all but one of the 18-man patrol. These actions marked a significant escalation of the conflict. In response, Counties Cork, Kerry, Limerick, and Tipperary – all in the province of Munster – were put under martial law on 10 December under the Restoration of Order in Ireland Act;
Local Government (Ireland) Act 1898 of the Irish Free State and Northern Ireland. The Act caused a number of county boundaries to be modified. This was for several reasons: The extents of the new administrative counties and county boroughs, which came into effect on 18 April 1899, were defined by orders of the Local Government Board for Ireland. There were no changes to the boundaries of the counties of Cavan, Cork, Donegal, Fermanagh, Kerry, Kildare, King's (Offaly), Leitrim, Limerick, Longford, Meath, Monaghan, and Tyrone; nor to those of the county boroughs (previously counties corporate) of Cork, Dublin, Limerick, and Waterford. Changes elsewhere were as follows: