Complex sentence: Meurig was the son of Ithel, grandson of Rhydd and great-grandson of Iestyn ap Gwrgant, the last king of Gwent (reigned 1081--1091) before its conquest by the Normans.
Split into simpler sentences: Meurig was the son of Ithel, grandson of Rhydd and great-grandson of Iestyn ap Gwrgant. Iestyn had been the last King of Gwent (reigned 1081--1091) before its conquest by the Normans.