This is what happens when you disobey the king, your uncle. Here, Oliver and Rollant are dispatched by King Karlamagnus to the city of Nobilis, to which they must lay seige. They have explicit orders to take King Ful, who rules over Nobilis, alive.

And when they arrived there, King Ful had drawn up a great host against them. Then Rollant said to Oliver, "Do you want to hear about some foolishness, comrade?" says he.

Oliver answers, "I have heard enough; but what is it?"

Rollant replies, "Karlamagnus, my kinsman," said he, "ordered us not to kill King Ful, who has not been captured yet."

Oliver answers, "It would be a marvel," says he, "for him to take care of him, if I can capture him."

Then they all armed themselves and arranged their host in three ranks with a hundred thousand in each; Rollant and Oliver spurred their horses and gallopped forward from the division against King Ful.

King Ful struck his spear into Oliver's shield so that it stuck fast there. But Rollant repaid him well, striking his spear into the middle of the king's shield and into his side, and knocked him off his horse. In that moment Oliver struck at King Ful with his sword, slashing into his neck against the helmet and head, through to the chin.

Then all their host joined them, and a great part of the heathen army was killed, as well as those who were in the city; and they captured the town and made it submit to King Karlamagnus. After that, Rollant and Oliver and all their host went and washed all of the battlefield, so that King Karlamagnus would not see the blood that had been shed.