Arthurian Legend , group of tales that developed in the Dark Ages concerning Arthur , semihistorical king of the Britons , and his knights . The legend is a complex weaving of ancient Celtic mythology with later tradiditions around a core of possible historical authenticity.

The earliest references to Arthur found in Welsh sources - the poem , Y Gododdin ( c. 600 ) , histories written in Latin , in the 9th and 10th centuries , and tales in the Welsh story collection The Mabinogion (c. 1100 ) . In one of these tales Arthur’s wife , Guinevere , and his knights Kay , Bedivere and Gawain make their appearance . The earliestcontinuous Arthurian narrative is given in the Historia Regum Britanniae (c . 1139 ) by the English writer Geoffrey of Monmouth . Here Arthur is identified as the son of the British king Uther Pentragon and his counsellor Merlin is introduced . The Historia mentions the isle of Avalon , where Arthur went to recover from wounds after his last batlle , and it tells of Guinevere’s infidelity and the rebellion instigated by Arthur’s nepheww Mordred .