Trim Castle, the largest Anglo-Norman castle in Ireland, was constructed over a thirty-year period by Hugh de Lacy and his son Walter. Hugh de Lacy was granted the Liberty of Meath by King Henry II in 1172 in an attempt to curb the expansionist policies of Richard de Clare, (Strongbow). Construction of the massive three storied Keep, the central stronghold of the castle, was begun c. 1176 on the site of an earlier wooden fortress. As this site is managed by the OPW, school tour visits are permitted free of charge provided certain conditions are met.