William Herbert, 1st Earl of Pembroke KG (c. 1423 – 27 July 1469), known as "Black William", was the son of William ap Thomas, founder of Raglan Castle, and Gwladys ferch Dafydd Gam, and grandson of Dafydd Gam, an adherent of King Henry V of England.
His father had been an ally of Richard of York], and Herbert supported the Yorkist cause in the Wars of the Roses. Herbert was rewarded by King Edward IV with the title Lord Herbert of Raglan in 1461 (having assumed an English-style surname in place of the Welsh patronymic), and invested as a Knight of the Garter.
Soon after the decisive Yorkist victory at the Battle of Towton in 1461, Herbert replaced Jasper Tudor as Earl of Pembroke which gave him control of Pembroke Castle. However, he fell out with Lord Warwick "the Kingmaker" in 1469, when Warwick turned against the King. William and his brother Richard were executed by the Lancastrians, now led by Warwick, after the Battle of Edgecote Moor, near Banbury.
Herbert was succeeded by his son, William, but the earldom was surrendered in 1479. It was later revived for a grandson, another William Herbert, the son of Black William's illegitimate son, Sir Richard Herbert of Ewyas.
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