The first castle on this site was built by Geoffrey de Cusack, an Anglo-Norman who came to Ireland with Hugh de Lacy. The new overlords built castles to protect their territories around Dublin and the east coast, a region known as ‘The Pale’. Killeen was built in 1181 beside a tiny ruined church dedicated to St Fanchea. For the next few centuries, the de Cusacks and their descendants, the de Tuits lived at Killeen, until around 1402, when Sir Christopher Plunkett married into the family, beginning the long association with the Plunkett family and the Killeen and Dunsany estates. The Plunketts later became the Earls of Fingall and were one of the few one of the great Anglo-Irish families to survive into the 20th century. In the early 1800s the 8th and 9th Earls engaged renowned architects, Francis Johnson and James Sheil to modernize the castle to create what you see today. The 12th and last Earl of Fingall sold the castle in 1951 and the estate was then run by its new owners as a stud farm. In 1981 the castle fell victim to fire, and lay dormant and in ruins until 1997 when Snowbury Ltd purchased it and its grounds with a vision to create a magnificent hotel and golf course. Within the grounds are the ruins of Killeen Church, now a national monument. This church was built by Sir Christopher Plunkett (c.1370–c. 1445). It is believed that the tomb within the church holds he and his wife, Lady Joan de Cusack remains.