User blog comment:Bolg, son of Azog/Morgoth and the Ring/@comment-207.6.59.214-20150210100759

Well Morgoth put most of his power into all his evil and into all his servants, so I imagine that most of the original power that Sauron had and that he put into the ring most likely came from Morgoth himself, way back when Sauron was his second in command.