Although the current Clontarf Castle is quite modern there has been a castle on its grounds since 1172. It's site was home to one of the greatest battles in Irish History “The Battle of Clontarf”.
Clontarf Castle was owned by the Knights Templar until their dissolution in 1308.
Queen Elizabeth I gave the castle to an Englishman, Geoffrey Fenton, whom she named as her Secretary of State for Ireland. It then passed through marriage to one of his descendants George King. who participated in the Irish Rebellion of 1641, and because of this the castle and its surrounding lands were taken from him.
The castle was opened to the public as a hotel in 1997.
George Frideric Handel the German composer was a frequent visitor to the castle when he was in Dublin in 1742 composing his 'Messiah'. rock band Thin Lizzy have a song about Clontarf Castle called “The Friendly Ranger at Clontarf Castle”. Can't say I have ever heard it though :-). Must have been a B-side !
