'Oh, for the love of God, sire!' she cried, 'do not come up! Three of the fairest knights ever seen are playing chess and backgammon in a chamber; they are my brothers, but they will turn wild as soon as they see you.'

'Damsel,' said Perceval, 'if it please God and you, they will not. But it is good to see such a miracle, for it is only right that those who do not believe in God should turn mad when they see things that come from Him.'

And so, in spite, of the maiden's words, Perceval climbed up to the hall, fully armed, and she followed him as quickly as she could. The three knights saw Perceval in all his armour, and when they saw the cross on his shield they leapt up straightaway, wild now and furious, rolling their eyes and tearing at themselves and howling like demons. They rushed to snatch up their guisarmes and swords and would gladly have attacked Perceval, but they could not, for it was not God's wish. Instead they attacked one another and hacked and hewed each other to pieces, refusing to stop despite the maiden's pleas. Perceval gazed at the wondrous deaths of these men, and so did the maiden, who was deeply grieved.

'Oh, damsel,' he said, 'do not weep, but repent of this false faith, for all those who will not believe in God will die in madness like demons.'

Perlesvaus