Thomas de Berkeley, 5th Baron Berkeley Thomas de Berkeley, 5th Baron Berkeley Thomas de Berkeley, 5th Baron Berkeley (5 January 1352/53 – 13 July 1417), "The Magnificent", of Berkeley Castle and of Wotton-under-Edge in Gloucestershire, was an English peer and an admiral. His epithet, and that of each previous and subsequent head of his family, was coined by John Smyth of Nibley (d.1641), steward of the Berkeley estates, the biographer of the family and author of "Lives of the Berkeleys". He was born at Berkeley Castle in Gloucestershire, the son and heir of Maurice de Berkeley, 4th Baron Berkeley by his wife Elizabeth le Despencer. In
Margaret Mortimer, Baroness Berkeley Margaret Mortimer, Baroness Berkeley Margaret Mortimer, Baroness Berkeley (2 May 1304 – 5 May 1337) was the wife of Thomas de Berkeley, 3rd Baron Berkeley. She was the eldest daughter of Roger Mortimer, 1st Earl of March, the "de facto" ruler of England from 1327 to 1330, and his wife Joan de Geneville, Baroness Geneville. Margaret Mortimer was the eldest of the twelve children of Roger Mortimer, 1st Earl of March and Joan de Geneville, Baroness Geneville. Her paternal grandparents were Edmund Mortimer, 2nd Baron Mortimer and Margaret de Fiennes. Her maternal grandparents were Piers de Geneville, of Trim Castle