I think Alexander refused to wear a mask in public because it would hide his handsome features. No plague was going to mess with HIS self-presentation.
Seriously, a great story about Alexander the Great, maybe apocraphyl, but it is in all the histories of philosphers:
When Alexander the Great conquered Athens, he went to find the philosopher Diogenes, founder of the school of Cynics.
He found Diogenes stretched out lying in the sun on a lawn.
He went up to him and told the great thinker: "I am Alexander, conqueror of the world, the greatest living leader, perhaps the greatest man in history, and you are Diogenes, the greatest living thinker and philosopher ! How remarkable that we should finally meet this historic day !"
Diogenes replied "Hey man, could you move over a little. You're blocking the sun."