The Earl of Warwick is one of the oldest English earldoms. The medieval earldom was held to be inheritable through a female line of descent, and thus was held by members of several families. It was traditionally associated with posssession of Warwick Castle, and when the 11th Earl entailed the castle to his heirs male, he probably intended to entail the earldom as well.
It was held by several Earls, until Edward Plantagenet, the eighteenth Earl, whose title was attained due to his treason. The title was next conferred upon John Dudley, 1st Duke of Northumberland. At Dudley's death the dukedom was forfeit for his treason, but the earldom passed to his son John, and then his other son Ambrose. At Ambrose's death, the earldom became extinct.
The Earldom was for a third time created for Robert Rich, 3rd Baron Rich. However, unlike previous holders of the title, the Rich family did not control Warwick Castle, ancient seat of the Earls of Warwick. This was in the hands of the Greville family, who were at the time Barons Brooke. At the death of the eighth Rich Earl, the title became extinct, and was granted to Francis Greville, 1st Earl Brooke, thus uniting again the title and castle. The new Earl, now The Earl Brooke and of Warwick, applied for permission to use the more prestigious Warwick title alone, and although such permission was never granted ceased the use the Brooke Earldom in his style, and thus the Greville Earls have always been known (except in the House of Lords) simply as The Earl of Warwick.
Wales in 1471, married Richard, duke of Gloucester, afterwards Richard III.
Plantagenet, 18th earl of Warwick (1475-1499), son of the duke of Clarence, and therefore the Yorkist heir to the crown.
Northumberland (q.v.), who was created earl of Warwick in 1547, on account of his descent from Margaret, countess of Shrewsbury, daughter of Richard Beauchamp, earl of Warwick.
Warwick was the eldest son of Richard Neville, 5th Earl of Salisbury and Alice Montagu, Countess of Salisbury.
Warwick was attainted as a "traitor" in 1470, and was forced to flee to France; where he came to form an alliance with his old enemy Margaret of Anjou, queen of King Henry VI of England.
News of this drove Charles the Bold, the Duke of Burgundy, to assist Edward with funds and an army to invade England in the spring of 1471.