From The Stargate Omnipedia

Knight who had once known Merlin during the days of King Arthur's Round Table. When SG-1 located and thawed the Ancient from his stasis unit he mistook Cameron Mitchell for his old friend Percival.

After Merlin's memories were merged into Daniel Jackson's mind, Daniel admitted that Mitchell really does look like Percival.


The Quest, Part 2 - After a thousand years in an Ancient stasis unit, Merlin emerges believing he is surrounded by his old friends.