Guy de Beauchamp, 10th Earl of Warwick (c. 1272 – 12 August 1315) was an English magnate, and one of the principal opponents of King Edward II and his favourite, Piers Gaveston.

Guy de Beauchamp is today remembered primarily for his part in the killing of Gaveston, but by his contemporaries he was considered a man of exceptionally good judgement and learning.

Next to Lancaster, he was the wealthiest peer in the nation, and after his death his lands and title were inherited by his son, Thomas de Beauchamp, 11th Earl of Warwick.

His mother was Maud FitzJohn, daughter of John Fitzgeoffrey, who was Justiciar of Ireland and a member of the council of fifteen that imposed the Provisions of Oxford on King Henry III.

[1] William de Beauchamp was a capable military commander, who played an important part in the Welsh and Scottish wars of King Edward I.

[14] At this point his father was already dead, but it was not until 5 September that Guy did homage to the king for his lands, and became Earl of Warwick[13] and hereditary High Sheriff of Worcestershire for life.

In 1299 he helped negotiate the Treaty of Montreuil betrothing Prince Edward of Caernarfon to the French princess Isabella and he was also present at the king's own wedding to Margaret of France at Canterbury, and in 1300 he took part in the Siege of Caerlaverock Castle.

[6] Early in 1307, Edward I made his last grant to Warwick, when he gave him John Balliol's forfeited lordship of Barnard Castle in County Durham.

[14] Gaveston was a relative upstart in the English aristocracy, and made himself unpopular among the established nobility by his arrogance and his undue influence on the king.

Another source of contention was Edward abandoning his father's Scottish campaigns, a policy that opened the Border region up to devastating raids from the Scots.

[6] They still did, and at the parliament of March 1310, the king was forced to accept the appointment of a commission to draft a set of ordinances towards reform of the royal government.

[23] The leaders of these so-called Lords Ordainers were Robert Winchelsey, Archbishop of Canterbury, on the side of the clergy, and Warwick, Lincoln and Lancaster among the earls.

[25] Thomas of Lancaster, who was Lincoln's son-in-law and heir, was the king's cousin and the wealthiest nobleman in the realm, but at this point he took a less active part in the reform movement.

Gaveston ensconced himself at Scarborough Castle, and on 19 May 1312, agreed on a surrender to Aymer de Valence, Earl of Pembroke, as long as his security would be guaranteed.

[35] The king himself swore vengeance on his enemies, but found himself unable to move against them immediately, partly because they were in possession of a number of highly valuable royal jewels taken from Gaveston.

Likewise, when the earl of Lincoln died in 1311, he supposedly instructed his son-in-law Thomas of Lancaster to heed the advice of Warwick, "the wisest of the peers".

[1][6] Later historians have reflected this view; in the 19th century, William Stubbs called Warwick "a discriminating and highly literate man, the wisdom of whom shone forth through the whole kingdom".

Warwick's death came at an inconvenient time and Thomas of Lancaster proved unequal to the task of governing the nation, so that further years of conflict and instability followed.

Nevertheless, the problems of Edward II's reign were deep, and in the words of Michael Hicks: "one must doubt whether even Warwick could have brought unity as one chronicler supposed".