Well i am really not sure how much i can type here. But this is the information I have.
MEILER FITZHENRY. (born 1118, died 1220) JUSTICIAR of IRELAND, was the son of Henry Fitzroy Prince of England, the illegitimate son of Henry I King of England, by Nesta, the wife of Gerald of Windsor, and the daughter of Rhysab Tewdr, King of South Wales. Nesta Princess of Wales, previous to her first marriage to Stephen, had been concubine to Henry I, by whom she had two sons-Robert, Earl of Gloucester, and Henry Fitzroy, father of Robert and Meiler Fitzhenry from whom descend the Fitzhenrys of Ireland. Meiler was the grandson of Henry I, first cousin of Henry II, and related to the noblest Norman and native families of South Wales. Robert Fitzstephen, Maurice Fitzggerald, and David II, Bishop of St David's, were his half brothers. Raymond LeGros and Giraldus Cambrensis were among his cousins.
In 1157 his father Henry Fitzroy was slain during Henry II's campaign in Wales, when Robert Fitzstephen so narrowly escaped. Meiler, then quite young, now succeeded to his father's possessions of Narbeth and Pebidiog, the central and northeastern parts of modern Pembrokeshire.
In 1169 he accompanied his uncle Robert Fitzstephen on his first expedition to Ireland. He first distinguished himself in the invasion of Ossery along with his cousin Robert de Barry, brother of Giraldus. The French poet Regan fully corroborates as regards Meiler. If the partial testimony of their kinsman is to be credited, Robert and Meiler were always first in every daring exploit.
In 1173 the return of Richard DeClare, "Strongbow", to England threw all Ireland into revolt. Meiler was then in garrison at Waterford, and made a rash sortie against the Irish. He pursued them into their impenetrable woods and was surrounded. But he cut a way through them with his sword, and arrived safely at Waterford with three Irish axes in his horse and two on his shield.
In 1174 he returned with Raymond to Wales, but when Richard DeClare, "Strongbow", brought Raymond back, Meiler came with him and received as a reward the more distant cantred of Offaly'. In October 1175, he accompanied Raymond in his expedition against Limerick, was the second to swim over to Shannon, and with his cousin David, stood the attack of the whole Irish host until the rest of the army had crossed over. He was one of the brilliant band of Geraldines who under Raymond met the new governor, William Fitzaldhelm at Waterford, and at once incurred his jealous hatred.
Hugh de Lacy, the next judiciar, took away Meiler's Kildare estate, but gave him Leix in exchange. This was in a still wilder, and therefore as Giraldus thought, a more appropriate district than even the march of Offaly' for so thorough a border chieftain. In 1182 Lacy again became justice and built a castle on Meiler's Leix estate at Tahmeho, and gave him his neice as a wife. It seems probable that Meiler had already been married, but his hitherto had no legitimate children. This childlessness was in Giraldis' opinion God's punishment to him for the want of respect to the Church.
Giraldus gives us a vivid picture of his cousin in his youth. He was a dark man, with black stern eyes and keen face. In stature he was somewhat short, but was very strong, with a square chest, thin flanks, bony arms and legs, and a sinewy rather than fleshy body. He was high spirited, proud, and brave to rashness. He was anxious to excel, but more anxious to seem brave than to be so. His only serious defect was his want of reverence to the Church. *
In June 1200 Meiler was in attendance on King John in Normandy, and on October 28th of that year received a grant of two cantreds in Kerry, and one in Cork. About the same time he was appointed to the care and custody of all Ireland as chief justiciar, the king reserving to himself pleas touching the crown, the mint, and the exchange. During his six years' government Meiler had to contend against very great difficulties, including the factiousness of the Norman nobles. John de Courci, the conqueror of Ulster, was a constant source of trouble to him. The establishment of Hugh de Lacy as Earl of Ulster in 1205 was a great triumph for Fitzhenry. Before long however, war broke out between Lacy and Fitzhenry.
(whew, not used to this much typing, Part II to follow).