Guy de Beauchamp, 10th Earl of Warwick is the son of William de Beauchamp, 9th Earl of Warwick and Maud FitzGeoffrey. Guy had already distinguished himself in the Scottish Wars and was one of the Ordainers, who sought to restrict the powers of the King. Guy de Beauchamp was one of the chief adversaries of Piers Gaveston, King Edward's favourite, who often referred to Guy as The Mad Hound, due to the Earl's habit of foaming at the mouth when angry. In 1312, Guy de Beauchamp captured Gaveston and took him to his principal residence Warwick Castle where Gaveston was held prisoner and afterwards murdered.

He first married Isabel de Clare, the daughter of Gilbert de Clare, 6th Earl of Gloucester and Alice de Lusignan of Angoulême, but the marriage, which had produced no children, was annulled. On 28 February 1310, less than three years after the death of her first husband, Guy de Beauchamp married Alice de Toeni, daughter of Ralph VII de Toni.

Child of Guy de Beauchamp and unnamed partner:

• Maud de Beauchamp (died 1366), married Geoffrey de Say, 2nd Lord Say, by whom she had issue.

Children of Guy de Beauchamp and wife Alice de Toeni:

• Thomas de Beauchamp, 11th Earl of Warwick (14 February 1313/1314 – 13 November 1369), married Katherine Mortimer, by whom he had fifteen children.
• John de Beauchamp, Lord Beauchamp KG (1315 – 2 December 1360), carried the royal standard at the Battle of Crecy
• Elizabeth de Beauchamp (c. 1316–1359), married in 1328, Thomas Astley, 3rd Lord Astley, by whom she had a son William Astley, 4th Lord Astley.
• Isabella de Beauchamp, married John Clinton.
• Emma de Beauchamp, married Rowland Odingsells.
• Lucia de Beauchamp, married Robert de Napton.

Following the sudden death of Guy de Beauchamp at Warwick Castle on 28 July 1315, which was rumoured to have been caused by poisoning, Alice married thirdly on 26 October 1316, William la Zouche de Mortimer, 1st Lord Zouche de Mortimer

Links to additional material:

• http://en.wikipedia.org/wiki/Guy_de_Beauchamp,_10th_Earl_of_Warwick
• http://thepeerage.com/p3204.htm