Who is Arthur from Here Lies Arthur and what is their importance?

Arthur is the son of Uthr, the brother of Cei, and the uncle of Bedwyr and Medrawt. His first wife is Cunaide and his second wife, married in a Christian ceremony, is Gwenhwyfar—making her his legal wife, though he maintains a close, sexual relationship with Cunaide throughout the novel and holds only a distant relationship with Gwenhwyfar. Arthur's genesis comes about when the kingdom, briefly united under his successor, begins to fall apart into fiefdoms. Arthur maintains control of a large unit of heavy cavalry that forms the nucleus of his power. Arthur attracts the attention of the bard Myrdden who believes that Arthur is the strongest of the fighting warlords and thus has the greatest chance of reuniting Britain arms to drive out the Saxon invaders. To this end, Myrdden becomes the brains of the operation while Arthur provides the brawn. In the novel, Arthur is presented as an avaricious and jealous man, driven by the urge to conquer and possess rather than any noble desires.