The Barracks and castle saw many battles the main battle was the Williamite/Jacobite wars in 1690/91 which caused over 2000 deaths here in Athlone and saw the jacobite Army defeated both here in Athlone and At the battle field of Augrim and the death of the Jacobite Commander St Ruth
Battle of the Boyne
a new riverside road to accommodate travellers to the Midland Great Western Railway Station resulted in the walling of the barracks and the building of a water gate with quay facing it.
Around the same time the main barracks entrance on the Market Square was rebuilt and fortified by the addition of a capponière.(Military word for cover as in roof of building)
Other additions to the barracks before 1921, such as messes, cookhouses, school house, chapel, ball alley, reading rooms, married quarters and gymnasium, facilities to improve the lot of the soldier as part of the reforms that followed the shortcomings exposed by the Crimean War.
The army recruited successfully in Athlone during the nineteenth century, and officers and other ranks were involved in the social and sporting life in the locality.
During World War I the barracks was an important depot for the training and dispatch of soldiers to the Western Front. Extra accommodation in tents was provided in the nearby Ranelagh playing fields.
In the War of Independence the barracks was the headquarters of the 5th Division’s Athlone Brigade area, responsible for security throughout much of the west and midlands.
After the Anglo-Irish treaty of 1922 the barracks was vacated by the British army and taken over in a peaceful ceremony by the new Irish army under General MacEoin.
During Civil War it was the administrative and support centre for operations against anti-treaty forces in the west of Ireland.
The post-Civil War downsizing of the army was a low point for Custume Barracks. The number of serving personnel was reduced, and the administration of the Western Command transferred to the Curragh.
Barrack property was given as sites for SS Peter and Paul’s Church and new government buildings on Barrack Street. These developments necessitated the opening of a new main entrance on Grace Road, flanked by recesses formed from the stones of the divided capponière.