In "Arthur and King Lucius" Malory has transformed the alliterative Morte Arthure, one of the earliest full-scale tragedies in English, into a tale of the Round Table at its happiest and, in some ways, most noble. For the overweening pride of the Arthur in his source, Malory substitutes a just and wise king; and the poem's tragic conclusion, Arthur's return to fight Mordred, lover to Guinevere, Malory drops for a joyful reunion of faithful husbands and wives. In the source, Launcelot is a minor figure, Gawain central. Malory elevates Launcelot, retains the dignity of Gawain, making only this distinction between them: Gawain's rash action in murdering Gains is left unjustified, while the action of Launcelot and Cador on the road to Paris, labeled as rash in the source, is carefully rationalized here.
But the most important change is Malory's introduction of the marriage theme. The giant of St. Michael's Mountain wants Arthur's beard in the source. In Malory we are told twice that he wants Guinevere. The murdered duchess in this episode is changed from a cousin of Arthur to the wife of a cousin. And so, throughout Malory's version, all references to marriage in the source are retained and new references are introduced. At the same time, other love relationships are introduced and developed here. It is in this tale that we first see Gawain and Launcelot as devoted friends, fighting in one another's behalf Arthur's love for Kay, present in the source, is retained and made central.
