The Archmage is a mysterious and powerful entity that was bound at the center of the Sorcerer’s World for millennia. He was bound there by “a race of beings so old that the gods of ancient Olympus believed them mythical” according to Mister E.
In the 30th Century the Archmage broke free, and wild magic was unleashed on the universe. This also caused science to stop working properly.
The Legion of Super-Heroes opposed the Archmage, though he ended up defeating himself when he destroyed the Sorcerer’s World, which was the source of his own power.