Leodogran, the king of Cameliard, had only one daughter, Guinevere. She was the most beautiful of all women and he loved her dearly. This was in the time before Arthur came, when many petty kings and feudal lords ruled in England, and the country was torn asunder by their disputes and wars. In addition, England was frequently subjected to raids by pagan barbarians from the north, who came in ships and laid waste to vast areas. Many sections of the country became a wilderness again, and beasts were more at home in them than men were. Two kings, Aurelius and Uther, had attempted to reunite the kingdom, but their efforts were unsuccessful. After them, however, Arthur was able for a while to make a nation of England and to rule it through the strength of his Round Table.
At the time the tale begins, Cameliard is a deserted wasteland. Leodogran is not strong enough to deal with the situation and often wishes helplessly that the Roman legions would return to restore order. He is attacked nearly simultaneously by Urien, a neighboring king, and a heathen raiding party. Both attackers leave fire and destruction in their wake.
Meanwhile, Arthur has been crowned, despite the protests of those who claim he is not the rightful heir to the throne. Leodogran immediately sends to the new king for help. Arthur responds at once to this request and starts his first campaign. At Cameliard he sees Guinevere and instantly falls in love with her. Continuing on his way to the battle, Arthur muses about his love for Guinevere and decides that, with her at his side, he will be able to do great things and be a good king. He plans to ask for her hand in marriage.
In the battle which follows, Arthur and his knights defeat a coalition of enemy kings, including Urien, Carados, Lot of Orkney, and several others. Arthur is pleased with his victory and especially with the prowess shown by the knight whom he loves most, Lancelot. The two warriors swear an oath of eternal loyalty to each other; Lancelot says:
"Sir and my liege," he cried, "the fire of God
Descends upon thee in the battle-field.
I know thee for my King!"
"Man's word is God in man;
Let chance what will, I trust thee to the death."
After the battle Arthur sends three knights as messengers to Leodogran to ask for Guinevere in marriage. Her father is pleased by the offer, but is uncertain about what to do since he knows the rumors that Arthur is not of royal blood. He questions his faithful chamberlain, but gains no information from him.
Then Leodogran inquires about Arthur's background from the messengers. Bedivere, one of the knights, explains the tale of the king's birth. Many years before, in the time of Uther Pendragon, he says, Gorlois of Tintagil wed Ygerne. They had several daughters, among whom is Bellicent, the present queen of Orkney. In a war that followed, Gorlois was killed by Uther, and Tintagil Castle was captured. Uther, who had always lusted after Ygerne, forced her to marry him. Their son was Arthur. Uther died before the baby was born; so the child was secretly placed in the care of Merlin, in order to protect him from harm by rivals to the throne. He was raised by an old friend of Uther, Sir Anton, who had purposely acted as if Arthur were one of his own children. This is the basis for the rumors that Arthur was really the son of Anton or Gorlois, and not of Uther. But despite these whispered scandals, Merlin was able to have Arthur crowned when he came of age.
This story notwithstanding, Leodogran is still uncertain about Arthur's parentage and his legal right to the throne, and he doubts also Arthur's ability to hold onto his kingdom. Just at this time, Bellicent of Orkney and her sons, Gawain and Modred, visit Cameliard. The king questions her too, and she informs him of Arthur's exemplary character and great strength, but she has no precise knowledge about his birth. Leodogran is still unable to make up his mind, but he has a dream which convinces him. He sends the messengers back to Arthur with his acceptance.
Upon learning the news, Arthur dispatches Lancelot and a party of knights to escort Guinevere to him. When she arrives, in May, they are married by Dubric, the head of the Church in Britain. A great banquet and happy celebrations follow the ceremony, and all of Arthur's followers are overjoyed at his good fortune.
Later on, Arthur refuses to pay the tribute demanded by envoys from Rome, and in twelve great battles he overcomes the heathen and firmly establishes his kingdom.