The sword image presumably connects to the battle there, and the knight Roland. Though some people seem to think it’s to do with King Arthur and the sword in the stone.
If your researching this clue I’d strongly recommend reading up on the battle of Roncevaux pass, the link is within the 470 clue.
If you like your literature it’s interesting to note that the battle is recounted in the song of Roland, which according to wiki is the oldest surviving major work of French literature.
Both Roland and Oliver have in my opinion a role to play in this clue.