Trim Castle is the largest, best-preserved & most impressive Anglo-Norman castle in Ireland. Trim get its name from the Irish Baile Átha Troim, meaning ‘Town of the Ford of the Elder Trees', indicating that this was an important fording point on the River Boyne. Such was the significance of this crossing point that by the fifth century a chieftain's dún (fort) and an early monastery were sited here.
Trim Castle was built in 1172, shortly after the arrival of the Anglo-Normans in Ireland. King Henry II granted his baron Hugh de Lacy the Kingdom of Meath, along with custody of Dublin. The King feared that another of his barons Richard de Clare (also known as Strongbow) might set up a rival Anglo-Norman kingdom in Ireland, and gave de Lacy Meath as a counterbalance to Strongbow's powerbase in the south of Leinster.