Following the signing of the Anglo-Irish Treaty of December 1921 and the establishment of the Irish Provisional Government the troops in the barracks decided to support the anti-treaty side in the Irish Civil War and put the barracks in a state of defence. Troops of the National Army soon occupied the town, and were prepared to attack the barracks. Through the intervention of Dr. John Harty, then Archbishop of Cashel and Emly, hostilities were called off and the troops in possession were allowed to evacuate. After the legal establishment of the Defence Forces in October 1924 the Irish Army remained in possession until 1929.