In 1375, the castle was granted to James Butler, newly-created Baron of Cahir, for his loyalty to Edward III. The Butlers of Cahir sided with the Irish in the Elizabethan wars, and in 1599 the castle was captured after a three day siege by the army of the Earl of Essex and was for a year put under the charge of Sir Charles Blount.
During the Irish Confederate Wars the castle was besieged twice. In 1647 George Mathew, the guardian of the young Lord Cahir, surrendered to Lord Inchiquin following his victory at the battle of Knocknanauss. In 1650 he surrendered again to Oliver Cromwell, during his conquest of Ireland without a shot even being fired.
The Great Hall was partly rebuilt in 1840.
In 1961 the last Lord Cahir died and the castle reverted to the state.
The castle was built in two parts, with the side now by the street being built 200 years before the side now housing the audio-visual show.
Cahir Castle is one of the largest and best preserved castles in Ireland. It is one of Ireland's best known tourist attractions.
Cahir Castle was built originally in the 13th century on a site of an earlier native fortification called a cathair (stone fort), which gave its name to the place.
Granted to the powerful Butler family in late 14th century, the castle was enlarged and remodelled between the 15th & 17th centuries. It fell into ruin in the late 18th century and was partially restored in the 1840s. Now a national monument, it is managed on behalf of the State by Dúchas.