Carrickfergus, in the east of Antrim just north of Belfast, became the centre of his small state established without permission of Henry - until he was dispossessed of it by Richard I who was also known as Richard the Lionheart. It seemed that he had somehow offended the new King of England.
So the castle passed into the hands of Hugh de Lacy, another Anglo-Norman, who was created Earl of Ulster by King John. De Lacy expanded the castle before it was finished around 1250 under Henry III.
Carrickfergus is referenced in a famous song recorded by almost everyone from the Clancy Brothers, Dubliners, Van Morrison, Joan Baez to Charlotte Church and is referenced even by Ed Sheeran.
The great Irish actor Peter O'Toole who coincidentally played Henry II in the 1964 film Becket was also a fan, having been involved in the modern rewrite of the song.
Reflection of the castle in the ebbing waters of Belfast Lough under a stormy sky.
A previous post here on panoramicireland.com referenced the naval skirmish between John Paul Jones's USS Ranger and HMS Drake just offshore from Carrickfergus.