Board Thread:Spoilers!/@comment-1916997-20151020145336/@comment-24674051-20151020201312

Well, IMDB is not the most reliable of sources... :p

But, more research into Vortigern shows that he was an actual king of the Brits back in the 5th Century (centuries prior to the reputed time of Arthur). Not too much is known about him, obviously. however, some legends indicate that he usurped the throne of England from Constantine III.

Now, how might this tie into Once, you might ask? A couple of ways, actually. Maybe Vortigen was the original owner of Excaliber and tried to fight the darkness. The blade was broken during the fight, but Vortigen managed control the darkness (possibly with help from Merlin and Nimue). But after the darkness started to grow, Nimue grew angry with Merlin (she was in a relationship with Vortigen) and trapped him a tree, and placed Excalibur in the stone.

All conjecture, mind you, and quite skimpy on details, but it is the start of a very bad idea.