"We've always tried to ground SG-1's stories as well as mythology in some form of Earth mythology and put a twist on it. Previous to this it was Egyptian mythology and the Goa'uld posing as Egyptian gods. Going forward, we had to decide what mythology we were going to next play on. We hadn't done the King Arthur/Avalon/ Merlin mythology before. With Merlin being one of the more famous magical figures, I thought it would be interesting if we revealed he was an Ancient. That Merlin had, in fact, returned to Earth from Atlantis after the war with the Wraith and settled on our planet."