Having secured his kingdom, Arthur undertook expeditions against the Scots, Picts, Irish, Icelanders, Norwegians, and the Gauls. All of these campaigns were victorious. He thereby became the chief king of Christendom, while foreign courts imitated the styles at Camelot. Only once during the rest of Arthur's reign did a foreign power — Rome — try to exact tribute from him, but Rome paid dearly for such presumption.
In the meanwhile Arthur was attracting many noblemen as knights to his court. Among these was Gawain, who came with his mother, Morgause. Although Morgause was married to King Lot, one of Arthur's enemies, she fell in love with the young king and conceived a child by him. Unwittingly Arthur had slept with his own half sister, the daughter of Ygraine and Gorlois. From this incestuous and adulterous union came Modred, the evil knight that would destroy Arthur and his court. Arthur learned the secret of his true parentage after that amorous encounter.
Arthur acquired his famous sword, Excalibur, in this way. He saved Merlin from three murderous rogues, and Merlin accompanied him to the wood where King Pellinore, a knight, was challenging all passersby. While Arthur was a brave, capable fighter, he was overmatched by King Pellinore, who was mighty and experienced in single combat. Arthur's sword broke and he was badly wounded. Pellinore knocked Arthur unconscious while wrestling and was about to slay him when Merlin cast a spell that put Pellinore to sleep. Arthur awoke and Merlin took him to a hermit who healed his wounds. Then Merlin and Arthur rode to a lake, in the middle of which was a hand clasping an upraised sword. A maiden in a small boat appeared and told Arthur that he could have the sword if he would grant her a request later. Arthur agreed, got into the boat and fetched the sword, Excalibur, which was encased in a jeweled scabbard. Thus Arthur obtained his fabulous sword from the Lady of the Lake. But as Merlin pointed out, the scabbard was more valuable, since while Arthur wore it his wounds would not bleed. On returning to his court, Arthur found that his knights respected him even more for undertaking an adventure like an ordinary knight.
