This national monument is Ardee Castle located on the main street of Ardee in county Louth. It is the largest fortified medieval tower house in Ireland. The original structure on this site was founded by an Anglo-Norman lord called Roger de Peppard in 1207. In the c.15th John St. Ledger built this castle to defend this frontier town on the edge of the ‘pale’ between the Anglo Normans and the Gaelic clans beyond. Over the years it was fought over by the O’Neills and the English and was even used by James II as his headquarters prior to the Battle of the Boyne. In 1805 it was converted into a courthouse and prison and today it continues to be used as a district courthouse and for local council’s administration.