William de Valence, 1st Earl of Wexford and 1st Earl of Pembroke, born Guillaume de Lusignan or de Valence (1225-1230 – May 16 or 18, 1296) was a French nobleman and Knight, who became important in English politics due to his relationship to Henry III. He was heavily involved in the Second Barons' War, supporting the King and Prince Edward against the rebels lead by Simon de Montfort. He took the name de Valence ("of Valence").

He was the fourth son of Isabella of Angoulême, widow of king John of England, and her second husband, Hugh X of Lusignan, Count of La Marche, and was thus a half-brother to Henry III of England, and uncle to Edward I. William was born at Valence, near Lusignan, sometime in the mid-to-late 1220s (his elder sister, Alice was born 1224, and two elder brothers followed her).

Move to England

The French conquest of Poitou in 1246 created great difficulties for William's family, and so he and his brothers, Guy de Lusignan and Aymer, accepted Henry III's invitation to come to England in 1247. The king found important positions for all of them; William was soon married to a great heiress, Joan de Munchensi or Munchensy (c. 1230 – after September 20, 1307), Lady of Swanscombe and Countess of Pembroke, the only surviving child of Warin de Munchensi, Lord of Swanscombe and Earl of Pembroke, and wife Joan Marshal, daughter and eventual co-heiress of William Marshal, 1st Earl of Pembroke. Her portion of the Marshal estates included the castle and lordship of Pembroke and the lordship erected earldom of Wexford in Ireland. The custody of Joan's property was entrusted to her husband, along with, apparently, the title of Earl of Pembroke and Earl of Wexford between 1250 and 1260.

The Second Barons' War

This favouritism to royal relatives was unpopular with many of the English nobility, a discontent which would culminate in the Second Barons' War. It did not take long for William to make enemies in England. From his new lands in South Wales, he tried to regain the palatine rights which had been attached to the Earldom of Pembroke, but his energies were not confined to this. The King heaped lands and honours upon him, and he was soon thoroughly hated as one of the most prominent of the rapacious foreigners. Moreover, some trouble in Wales led to a quarrel between him and Simon de Montfort, who was to become the figurehead for the rebels. He refused to comply with the provisions imposed on the King at Oxford in 1258, and took refuge in Wolvesey Castle at Winchester, where he was besieged and compelled to surrender and leave the country.

However, in 1259 William and de Montfort were formally reconciled in Paris, and in 1261 Valence was again in England and once more enjoying the royal favour. He fought for Henry at the disastrous Battle of Lewes, and after the defeat again fled to France, while de Montfort ruled England. However, by 1265 he was back, landing in Pembrokeshire, and taking part in the Siege of Gloucester and the final royalist victory at Evesham. After the battle he was restored to his estates and accompanied Prince Edward, afterwards Edward I, to Palestine. From his base in Pembrokeshire he was a mainstay of the English fights against the Welsh princes, assisting in the conquest of North Wales. He also went several times to France on public business and he was one of Edward's representatives in the famous suit over the succession to the crown of Scotland in 1291 and 1292.

William de Valence died at Bayonne on the 13 June 1296; his body is buried at Swanscombe or at Westminster Abbey.

William and Joan de Munchensi (described above) had the following children:

• Isabel de Valence (d. October 5, 1305), married before 1280 John Hastings, 1st Baron Hastings (May 6, 1262 – February 10, 1313). Their grandson Lawrence later became earl of Pembroke. They had:
• William Hastings (1282 – 1311)
• John Hastings, 2nd Baron Hastings (September 29, 1286 – January 20, 1325), married to Juliane de Leybourne (d. 1367)
• Sir Hugh Hastings of Sutton (d. 1347)
• Joan de Valence, married to John Comyn (the "Red Comyn"), Lord of Badenoch (d. murdered, February 10, 1306), and had
• Elizabeth Comyn (November 1, 1299 – November 20, 1372), married to Richard Talbot, Lord Talbot
• John de Valence (d. January, 1277)
• William de Valence (d. in battle in Wales in June 16, 1282), created Seigneur de Montignac and Bellac
• Aymer de Valence, 2nd Earl of Pembroke and Wexford in 1296 (c. 1270 – June 23, 1324), married firstly to Beatrice de Clermont and married secondly to Marie de Chatillon
• Margaret de Valence
• Agnes de Valence (b. about 1250)

References

• Ancestral Roots of Certain American Colonists Who Came to America Before 1700 by Frederick Lewis Weis, Lines: 80-29, 93A-29, 95-30, 154-29.