Who Is The Strongest Wizard That Ever Lived It Is

I'll go with Merlin too because i watched Disney's "the sword in the stone" and he could rocket himself to Bermuda! And he turned himeself into a common cold when he went against the purple dragon...(might have been pink)

Why i think it's MErlin is because in the HArry Potter books some of the wizards are something eomething order of MErlin. That means he must have been powerful.