The Roche Dure Tournament is a martial contest transformed into a public warning against King Arthur and Queen Guenever. Sir Tristram arrives bearing a shield supplied by Morgan le Fay, unaware that its image was devised to expose the love between Sir Launcelot and Queen Guenever and to bring dishonour upon the royal couple. When Arthur confronts him about it, the tournament’s spectacle gives way to a dangerous encounter: Tristram defeats Arthur and Sir Uwaine, then departs without knowing the shield’s full purpose.

Morgan le Fay’s Shield

At Morgan le Fay’s castle, she detained Sir Tristram until she learned his name. Having promised to let him go once he told her, she kept her word but asked him to carry a shield to the tournament at the Castle of the Hard Rock and perform as many deeds of arms as he could. Tristram accepted the request and the shield without knowing that it had been prepared as a weapon of accusation.

The shield was golden in appearance and showed a king and queen with a knight standing above them, one foot on each ruler’s head. Tristram asked what the image meant. Morgan identified the king and queen as Arthur and Guenever, and the knight as one who held them both in bondage and servitude, but withheld the knight’s identity. The image thus made a private accusation legible as a public emblem, while concealing the person at its center.

The account explains Morgan’s purpose: she loved Launcelot, who did not return her love or comply with her requests. She believed that Launcelot and Guenever loved one another, and arranged the shield to rebuke Launcelot and make Arthur understand the relationship. Tristram, however, did not know that the device was aimed at Launcelot when he agreed to bear it.

The Tournament and Its Audience

At the Roche Dure, the King of Scots and the King of Ireland opposed Arthur’s knights, and a great melee began. Tristram entered and performed striking deeds of arms, striking down many knights. He rode before Arthur with Morgan’s shield, so his battlefield success repeatedly brought its image into the king’s view.

Arthur marvelled at the shield’s design, while Guenever understood what it implied and grew troubled. A damsel in Morgan’s service, positioned in a chamber near Arthur, made the intended accusation explicit: she told the king that the shield had been made to warn him of his shame and dishonour, and that it concerned him and his queen. She then slipped away privately, and no one knew where she had gone. Her brief intervention supplied the charge but removed the messenger from questioning, leaving the shield as the visible evidence.

Guenever told Sir Ector de Maris that she believed Morgan had made the shield out of spite toward her and Launcelot, and feared that she might be destroyed. Arthur watched Tristram’s feats and wondered who the unknown knight was; he knew the man was not Launcelot. He had been told that Tristram was in Petit Britain with Isoud la Blanche Mains, and reasoned that, had the knight been in Logris, Launcelot or one of the companions who had sought Tristram would have found him. The shield therefore provoked suspicion even as Tristram’s identity remained concealed.

Arthur’s Challenge and Tristram’s Reply

As the King of Scots and the King of Ireland began to withdraw, Arthur resolved that the knight bearing the strange shield should not escape. He summoned Sir Uwaine la Blanche Mains, and the two approached Tristram together. Asked where he had obtained the shield, Tristram answered that Morgan le Fay, Arthur’s sister, had given it to him.

In the continuation, Arthur questioned whether Tristram deserved to bear arms he could not explain and asked him to disclose his name. Tristram replied that he could not describe the design, since that was no part of his charge, but trusted he could bear it honourably. He refused to give his name at that time. Arthur then demanded battle, making the encounter not merely a contest over heraldic knowledge but a test of honour and authority: Arthur insisted on an explanation, while Tristram maintained that he had no obligation to provide one.

Tristram also objected that Arthur was asking for combat after seeing how much effort he had already expended that day. He nevertheless agreed to fight and said he did not fear Arthur, even if Arthur thought he held an advantage. Arthur and Tristram charged one another. Arthur’s spear broke against Tristram’s shield; Tristram’s answering blow brought horse and rider to the ground and left Arthur seriously wounded in the left side. Sir Uwaine then challenged Tristram in turn. Uwaine’s spear also broke on Tristram’s shield, and Tristram struck him from his saddle.

Reversal and Aftermath

Tristram turned away after the two encounters and said he had already had enough to do that day; he had not needed to joust either knight. Arthur acknowledged that both had suffered through their own pride in demanding battle before learning Tristram’s name. Uwaine, despite his defeat, judged Tristram to be among the strongest knights living.

The tournament episode ends without Tristram learning the shield’s original purpose. He leaves and asks in various places after Launcelot, unable to discover whether he is alive or dead, a lack of news that brings Tristram sorrow. The narrative then carries him onward to a forest, where he sees one knight fighting nine. The shift from the royal confrontation to another unequal contest places the shield episode within Tristram’s continuing adventures, while its unresolved accusation remains with Arthur and Guenever. In the following account, the narrator clarifies the central irony: Tristram had not known why Morgan made the shield, nor could he tell Arthur the reason when challenged. He had carried a political insult without understanding it, yet his refusal to claim knowledge he did not possess helped turn the emblem into a fight with the king himself.