Maurice de Berkeley 1243 and, on 14 December 1243, he had livery of his father's lands. He fought in the war in North Wales and in 1264 he joined the Barons against King Henry III. Berkeley died on 4 April 1281 and was buried in St Augustine's Abbey in Bristol. Maurice de Berkeley Sir Maurice de Berkeley "the Resolute" (1218 - 4 April 1281), 5th (feudal) Baron de Berkeley, was an English soldier and rebel, residing at Berkeley Castle in the English county of Gloucestershire. Maurice was born in 1218 to Thomas de Berkeley and Joan de Somery. He married Isabel FitzRoy, the
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