William de Berkeley, 1st Marquess of Berkeley William de Berkeley, 1st Marquess of Berkeley William de Berkeley, 1st Marquess of Berkeley (1426 – 14 February 1492) was an English peer, given the epithet "The Waste-All" by the family biographer and steward John Smyth of Nibley. He was buried at "St. Augustine's Friars, London" according to one source, but most likely in the Berkeley family foundation of St Augustine's Abbey, Bristol. William of Berkley was born to James Berkeley, 1st Baron Berkeley, and Lady Isabel Mowbray at Berkeley Castle in Berkeley, Gloucestershire, in 1426. His first marriage was in 1466 to Elizabeth West, daughter of Reginald West, 6th
Berkeley family docent and genealogist at the Berkeley Castle listed the Barclay clan as also descending from the de Berkeley clan through the matriarchal line Alice De Berkeley -- the woman who married Robert Fitzharding and restored the family's name. Additionally, historians on Scottish clans and surnames point out that the Barclay clan spelling moves into the Berkeley (pronounced Bar-Clay) spelling. This descends from Sir Maurice Berkeley (by 1514–81), a politician who rose rapidly in the Tudor court. He came from the Berkeleys of Stoke Gifford, a cadet branch of the main Berkeley family, as a descendant of Sir Maurice de Berkeley