Legalities on using public figures ( Not celebrities ), historians, mythology, etc

So my question is what’s the legal status on using Public figures such as Obama ( Current American President ), other presidents, hitler, and other historians.

What about characters like zeus, medusa, Hercules, etc.?
How would one go about using the above characters for COMMERCIAL use?
Are there revenues to be paid? Is this public property? Must one be granted permission first?

Thanks so much in advance! I really do appreciate the support I have on the Unity forums.!
-Montray Davis

After a quick google, here is an article that might give you some context on using public figures.

http://www.reelseo.com/public-figures-video-marketing/

Enjoy :slight_smile: