Kay, Arthur and Merlyn are riding back from hunting. Kay asks Merlyn about Queen Morgause and what the Gaelic revolt is about. Merlyn replies that wars are never fought for one reason, although one reason is the feud between the Gaelic and the Gall (Arthur's monarchy). Arthur asks Merlyn to explain the history to him—seeing as though they are going to fight a war with the Gaelic Confederation.
Merlyn is still trying to teach Arthur about war and its justifications—how there might be a public reason for war, but a thousand private ones including desire for individual power. In a way he is warning Arthur not to trust simple justifications, but to try to understand the complex mechanisms behind peoples' actions.
Merlyn begins: three thousand years ago, the country belonged to a Gaelic race; they were then conquered by the Saxons; who, were then conquered by the Normans—Arthur's father. But, Merlyn continues, this is not the reason the war is going to happen; there is going to be a war because of Queen Morgause and because King Uther killed her father, the Earl of Cornwall. Arthur considers—he says that Queen Morgause is justified because of a personal reason and the Gaels are justified because of racial feud.
The story of the Gaelic feud illustrates a history of repression—but also a history so long distant it seems crazy that it still motivates people to go to war. Arthur however, at this stage, accepts these justifications. He does not see yet that it is not so different from what he experienced when he was an ant.
Merlyn ponders and says that if we think like that, there will never be an end to war because someone will always have a feud to finish—people need to accept the status quo. Besides, at least the Norman conquest united Britain, while the Gaels want to divide it once more. That, Merlyn argues, is why their reason is not a good one.
Merlyn's argument is that if you allow them to, people will always find justifications for violence. History is a history of warfare and feuds, but this history has to stop somewhere in order for the fighting to stop. This is something Arthur will try and achieve later in his life.