King John’s Castle is located in Carlingford in county Louth. This national monument was allegedly built for King John of England in 1200 however recent research suggests that it may have been built by the Norman, Hugh de Lacy. The castle offers stunning views across the lough towards the Mourne Mountains. The original castle consisted of an enclosed courtyard with two rectangular towers at the entrance and two storey buildings within. The eastern half of the castle was added in 1261 AD and included a number of rooms and probably a great hall. There were a number of alterations made to the castle over the centuries. The castle appears to have remained in English hands during the post-medieval period. Hugh O’Neill, Earl of Tyrone, tried to take the castle in a surprise attack in 1596 and the fortress changed hands several times over the following centuries. It also functioned as a hospital during the period leading up to the Battle of the Boyne.