The first Norman lord of Glamorgan was Robert Fitzhamon (d. 1107) (q.v. in D.N.B.). He left an heiress, Mabel (‘Mabli’ to the Welsh — she d. 1157), and Henry bestowed her on his son Robert, raising him, at some time in the year 1121-3, to the earldom of Gloucester, including the lordship of Glamorgan. He is lauded on all sides — as a brave soldier, as a wise statesman, and as a patron of letters. Geoffrey of Monmouth dedicated one version of his Historia to him. Robert Fitzhamon had already built Cardiff castle, and the town is referred to as a ‘borough’ in his time, but it was Robert of Gloucester and his son William (below) who granted Cardiff its charter in the oldest form known to us (Mathews, Cardiff Records, i, 10-11). He favoured the monastic movement: it was under his aegis that Richard de Grenville in 1130 founded Neath abbey, and it was Robert himself, in the last year of his life, who founded Margam. He d. 31 Oct. 1147.

All that is remembered of his son WILLIAM (d. 1183) is the somewhat ludicrous incident of 1158, when he and his family were abducted from Cardiff castle by Ifor Bach of Senghennydd (q.v.). Of William's children, the son, ROBERT, predeceased him in 1166. The eldest daughter, ISABEL (also called ‘Hawise’) was m. to prince (afterwards king) John; and although the marriage was dissolved, John clung to her lands till 1214. They finally passed to Isabel's sister AMICIA; her marriage to Roger de Clare ultimately brought Gloucester and Glamorgan into the hands of the Clare family (q.v.).