‘I’ll tell you all about it, sir, if you really wish to know. There’s a terrible pillar on Mount Dolorous – Merlin made it by magic long ago and set it on the peak. May God, the maker of the world, confound the one who put it there! It was a wicked deed! The pillar’s surrounded by fifteen crosses, but he walled up a demon inside it, and if anyone asks “Who’s in there?” he’ll go mad that instant, no matter how wise or sharp his mind, unless he’s the boldest knight in the world and the most upright in word and deed. Those two knights went and called at the pillar and asked “Who’s in there?”, and they instantly went wild! They lost their minds completely and hung us by our tresses from the tree, as you saw when you took us down! We loved them dearly, but now they’ve killed each other in their madness – yet not a month and a half ago they were the best
of friends! They’ve killed and destroyed one another through devilry and sin.’

‘Tell me their names if you will, dear girl,’ said Perceval. ‘Before the day’s out I’ll restore them to their senses if I can – unless they’re dead.’

‘Sir, one is the worthy Sagremor and the other’s Agravain – who’s neither weak nor faint-hearted in battle! They used to be such good friends!’

Gerbert's Continuation of Perceval