[Sidenote:  Treachery of Mordred.] Mordred the traitor immediately took advantage of his uncle’s absence to lay claim to the throne; and loudly declaring that Arthur had been slain, he tried to force Guinevere to marry him.  As she demurred, he kept her a close prisoner, and set her free only when she pretended to agree with his wishes, and asked permission to go to London to buy wedding finery.

When Guinevere arrived in that city she intrenched herself in the Tower, and sent word to her husband of her perilous position.  Without any delay Arthur abandoned the siege of Lancelot’s stronghold, and, crossing the channel, encountered Mordred’s army near Dover.

Negotiations now took place, and it was finally agreed that Arthur and a certain number of knights should meet Mordred with an equal number, and discuss the terms of peace.  It had been strictly enjoined on both parties that no weapon should be drawn, and all would have gone well had not an adder been lurking in the grass.  One of the knights drew his sword to kill it, and this unexpected movement proved the signal for one of the bloodiest battles described in mediaeval poetry.

    “An addere crept forth of a bushe,
    Stunge one o’ th’ king’s knightes on the knee. 
    Alacke! it was a woefulle chance,
    As ever was in Christientie;
    When the knighte founde him wounded sore,
    And sawe the wild worme hanginge there,
    His sworde he from the scabbarde drewe;
    A piteous case, as ye shall heare;
    For when the two hostes saw the sworde,
    They joyned in battayle instantlye;
    Till of so manye noble knightes,
    On one side there was left but three.”
                              King Arthur’s Death.

[Sidenote:  Arthur wounded.] On both sides the knights fought with the utmost courage, and when nearly all were slain, Arthur encountered the traitor Mordred.  Summoning all his strength, the exhausted king finally slew the usurper, who, in dying, dealt Arthur a mortal blow.  This would never have occurred, however, had not Morgana the fay, Arthur’s sister, purloined his magic scabbard and substituted another.  All the enemy’s host had perished, and of Arthur’s noble army only one man remained alive, Sir Bedivere, a knight of the Round Table.  He hastened to the side of his fallen master, who in faltering accents now bade him take the brand Excalibur, cast it far from him into the waters of the lake, and return to report what he should see.  The knight, thinking it a pity to throw away so valuable a sword, concealed it twice; but the dying monarch detected the fraud, and finally prevailed upon Bedivere to fulfill his wishes.  As the magic blade touched the waters Sir Bedivere saw a hand and arm rise up from the depths to seize it, brandish it thrice, and disappear.