Anasteu

A knight who lived almost a century before Arthur's time.

His father, King Assen, strongly disapproved of Anasteu's love for a lowborn woman. Fleeing his father's wrath, Anasteu took his lady into a forest, and carved a home for them out of solid rock, equipping it with various luxuries.

Later, this cavern served as Merlin's prison after he was shut up by the Lady of the Lake.