The author of Perceforest draws material from many sources, linking his prehistory of Arthurian Britain to numerous existing traditions and histories. In the following episode, he makes the murder of Julius Caesar an act of revenge for his destruction of Britain. Caesar has led an invasion in which the Romans have annihilated Perceforest's forces in an epic battle and devastated the whole kingdom. The young knight Ourseau, although raised as a Roman, has discovered he's the grandson of King Gadifer of Scotland and his wife the Fairy Queen, and that his father's brother was killed in the battle by Caesar himself. The Fairy Queen wants Ourseau to avenge his uncle's death with the head of Caesar's lance which dealt the mortal wound. She has recovered it from his uncle's body, and given it to Ourseau to carry back to Rome, where his father greets him with the utmost joy.