Arnulf de Montgomery ★

1060s–1090s

Born around 1066, son of Roger de Montgomery, Earl of Shrewsbury, and Mabel de Bellême. After 1093 he built up Pembroke and ruled much of Deheubarth, leaving Gerald de Windsor in command there.

1100s

Married Lafracoth, daughter of Muirchertach Ua Briain, King of Munster, around 1102. Joined his family's failed rebellion against Henry I that year and was banished and stripped of his lands; lived for a time in Ireland, then in Normandy and Anjou.

1110s–1120s

Died between 1118 and 1122; a tombstone bearing his name survives at Tulsk in Ireland.

Family Background

Arnulf de Montgomery was born around 1066, son of Roger de Montgomery, 1st Earl of Shrewsbury, one of the most powerful magnates in Norman England, and Mabel de Bellême, heiress of the lords of Alençon. Roger had not fought at Hastings but was richly rewarded on William the Conqueror's return in 1067, and by 1086 ranked among England's wealthiest tenants-in-chief; Arnulf first appears in the record as a charter witness around 1082–1083.

Conquest and Rule at Pembroke

After the death of Rhys ap Tewdwr, King of Deheubarth, in 1093 threw South Wales open to Norman conquest, Arnulf inherited and developed the earth-and-timber fortress his father had raised at Pembroke, a defensible promontory site contemporaries described as a "slender fortress built of stakes and turf." William Rufus rewarded him with the lordship, and Arnulf was addressed as "comes" (earl) by contemporaries including Archbishop Anselm of Canterbury. He installed Gerald de Windsor as his steward to actually run the lordship while he remained mostly in England, and by the early 1100s his domain stretched across much of Deheubarth and into Yorkshire, including the honour of Holderness.

Marriage to an Irish Princess

Facing King Henry I's charges of treason in 1102 alongside his brother Robert de Bellême, Arnulf sent Gerald de Windsor to Ireland to negotiate an alliance with Muirchertach Ua Briain, King of Munster, resulting in Arnulf's marriage to Muirchertach's daughter Lafracoth. Multiple contemporary sources record the union, and a surviving letter from Muirchertach to Archbishop Anselm thanks the archbishop for his intervention on behalf of "my son-in-law Arnulf." Historians debate whether Muirchertach's motive was international prestige, control of the lucrative Wales-to-Waterford trade route, or broader ambitions around the Irish Sea.

Rebellion and Downfall

Despite the Irish alliance, the wider Montgomery-Bellême rebellion against Henry I collapsed in 1102; Arnulf's chief contribution was a raid into Staffordshire alongside Robert de Bellême and Welsh allies. Henry methodically besieged and took the family's English strongholds — Arundel after three months, Tickhill immediately, Bridgnorth after a three-week siege — and once Robert de Bellême submitted at Shrewsbury, all three surviving Montgomery brothers were banished and stripped of their lands and titles.

Exile and Later Life

Arnulf fled to Ireland and lived for a time at Muirchertach's court, though sources differ on whether his father-in-law later forced him out or kept him in favor. He never recovered his English lands even after Henry's final victory over the Montgomery-supported Robert Curthose at Tinchebray in 1106, despite Archbishop Anselm's efforts at reconciliation, and spent his later years in Normandy and Anjou as a witness to charters of Count Foulques, retaining personal prestige even in exile. He died sometime between 1118 and 1122; a mortuary roll of 1122 commemorates him, and a tombstone bearing his name and that date survives at Tulsk in Ireland.

Legacy

Arnulf's career illustrates the path open to a Norman magnate's younger son: unable to inherit, he built power instead through conquest and calculated marriage. Though the Montgomery earldom did not survive him, his daughter Alice married Maurice FitzGerald, Lord of Lanstephan, carrying his line forward into the Anglo-Norman nobility of Wales and Ireland.