When Henry II departed Ireland in 1172, he handed over to Hugh de Lacy I the generous gift of the land of Meath; an enormous tract of land which covered the modern counties of Meath, Westmeath, and parts of Longford and Offaly. The tithes of this land together with lands in Dublin were granted to his favoured house of Llanthony situated on his estates in the valley of Ewyas in Wales. The subsequent arrival in Ireland of the knights of Hugh de Lacy I and the settlement of many of his Irish lands is recorded in the charters contained in the Irish cartularies of Llanthony Prima and Secunda. The growth of the Llanthony estates in Ireland both in terms of landholding and the holding of ecclesiastical revenues in the form of tithes can be mapped from a reading of the Llanthony charters in chronological order. For the most part, the charters are concerned with the tithes of land and ecclesiastical benefices both in the lordship of Meath and outside, granted to them by Hugh de Lacy I, his family and knights, and with the subsequent documentation in relation to those grants. A survey of the later charters reveals a complex prosopographical pattern of familial ties, interwoven with the tenacious patronage and advocacy of the landed gentry who identified with Llanthony down through the centuries, from the earliest settlement in the twelfth century until the Dissolution, in the sixteenth; a period of almost four hundred years.