William Beauchamp, 1st Baron Bergavenny

William was the fourth son of an English nobleman, Thomas Beauchamp, eleventh earl of Warwick (1313/14–1369), and of Katherine (d. 1369), daughter of Roger Mortimer, first earl of March. As a younger son he was destined to for the church and attended Oxford University from 1358 until 1361, but after the deaths of two elder brothers in quick succession, he was made a knight at 24 and began a career as a fighting knight round Europe.

In 1367 he accompanied Edward, the Black Prince on the Castilian campaign and later that year he and his brother Thomas Beauchamp (d. 1401), now heir to the earldom, went on crusade to Prussia. In 1370 he fought in Gascony, in 1373 he participated in John of Gaunt's expedition to France, and in 1381–2 in Edmund, earl of Cambridge's expedition to Portugal.

During the 1380s William received various grants including a life grant of 200 marks a year in 1380-81, and the priory of Pembroke in 1383. Most of his time William spent campaigning on the Continent and his role as captain of Calais from 1383-1389 kept him out of the intrigue against the king. Between 1390 and 1392 he became Baron Bergavenny, now a nobleman of considerable means.

At the time of his death Beauchamp was worth around £25,000, an equivalent of £9.3bn in 2010.