 An early lighthouse was established here in the 17th century by Robert Reading, and additional works (including the development of internal "citadel" defences) were added through the 18th and 19th centuries.The fort remained in use as a British Army barracks for two hundred years afterwards, before being relinquished by British forces following the Anglo-Irish Treaty of 1921.The fort fell out of use after being burned by retreating anti-Treaty forces during the Irish Civil War in 1922.