[1] He was the eldest son of Hugh de Lacy, a leading Cambro-Norman baron in the Norman invasion of Ireland, and Rohese of Monmouth.

[2] De Lacy did homage to Richard for his lands in Ireland in 1194, receiving his lordship of Meath.

[6] John attacked eastern Meath, and was joined by 400 of de Lacy's deserting followers.

[7] In 1211 de Lacy erected the castle on Turbet Island in the abortive Anglo-Norman attempt to gain control of West Ulster.

Attempting to secure support in Ireland against the brewing revolt that would lead to Magna Carta, John began negotiations to restore de Lacy to his lands in Meath in the summer of 1215.