On the unanimous advice of all his lords in council, Arthur chose the nobleman Count Angrs of Windsor, as the most trustworthy man in Britain, to serve as his regent while he paid Brittany a royal visit. Angrs was a brave, excellent knight and would have been a fine choice, had he not also been a criminal traitor.
In October, messengers from London and Canterbury crossed the Channel to bring Arthur, in Brittany, word that Angrs was planning rebellion. Comparing the Count of Windsor to Charlemagne's Ganelon - whom medieval Europe considered history's worst traitor after Judas Iscarot - Arthur hastened back to Britain, his army swelled with Bretons. Angrs, meanwhile, despoiled London to win over and enrich men of his own, then fled back to Windsor, which he had spent the summer fortifying.
At first the defenders, feeling secure, came out without their armor to sport and exercise on their own side of the Thames, in full view of Arthur's camp. This stirred up Sir Alexander and his Greek companions to make a sally across the ford, capturing four rebels, whom he gave to Guenevere. She would have followed the code of chivalry, which forbade slaying a defeated opponent who surrendered; but Arthur, following the code of feudal justice which required death to traitors, demanded them from her and had them drawn by four horses around Windsor.
Enraged at seeing men he had loved put to such a death, Angrs and his people planned a night attack of their own. The moonligt betrayed them, so the slaughter was great on both sides. Finally Angrs with seven surviving companions retreated to their stronghold in Windsor. Alexander, following, marshalled thirty knights (six of them Greeks) and came up with the ruse of trading their armor and shields with those of fallen rebels. Thus disguised, they easily gained admission to the castle, where the only men wearing armor were those just returned from the battlefield, who were already disarming. Though surprised and outnumbered as to armed warriors, the rebels still killed half of Alexander's men while losing only three of their own. Angrs himself slew Alexander's comrade Calcedor and might have proved Alexander's own match, had not being in the wrong worked to the count's disadvantage.
With his last four armed men, Angrs made it into the keep and expected help from the townspeople; but another of Alexander's companions, Nabunal, advised the infiltrators to bar the outer gates in time to keep the Windsor people out, and Alexander stunned Angrs into defeat with one great blow from a heavy pole that he found ready to hand, thus ending the rebellion. Before this Alexander's Greek companion, Macedor, had just been killed by Angrs.
Exhibiting Angrs to his subjects of Windsor, Alexander promised them mercy if they would surrender to the King, which they did. Angrs and his few surviving battle companions begged their captors to behead them at once, but this mercy would apparently have violated Alexander's knightly honor. Chrétien tells us only that Arthur wasted not a moment in bringing Angrs to justice, presumably drawing him with four horses.
P.A. Karr assume that this sentence extended to the armed men captured him. Since no mass slaughter is mentioned, this time Arthur apparently acted according to Alexander's hopes and treated Angrs' other people with mercy.
It has been suggested that Chrétien, in Cligés, patterned Count Angrs' rebellion on that of Mordred as described by Wace. If we do not dismiss Chrétien's account as an apocryphal reworking of the Mordred story, Angrs must have committed his villainy fairly early in Arthur's reign, for Alexander's son Cligés, not yet conceived at the time of Angrs' death, was later to make his own knightly mark at Arthur's court.
While Arthur is clearly in the right, his savagery in demanding strict "justice" contrasts tellingly with the mercy that Guenevere and Alexander would have preferred; in having his first rebel captives dragged to death in full sight of their comrades, moreover, Arthur shows questionable strategy, since the spectacle infuriates Angrs while graphically demonstrating to the rest of his men what they can expect should they surrender, thus ensuring that they will fight to the bitterest end.
Many of Angrs' knights, moreover, must have erred rather in adhering to their immediate loyalty than in breaking a more removed allegiance - a tangle of conflicting loyalties that could hardly have been lost on a medieval reader! - and for this some of them are shamefully tortured to death.
Angrs himself is shown not a monster of evil, but as a brave knight retaining some admirable qualities even in the midst of his villainy. Alexander succeeds in defeating him by means of a ruse that could strike an impartial judge as sneaky, underhanded, not playing fair, and hardly worthy of "the good guys" - yet for all his youth, idealism, mercy, and virtue, the heroic Alexander apparently sees nothing in the trick that might sit uncomfortably with his knightly honor. Cligés may have been largely ignored by later Arthurian writers because so much of it is only periphally an Arthurian romance. This seems unfortunate. Where is the novelist to explore the story of Angrs and his ill-fated rebellion for our own age.