Those nick-named Duke: John Wayne and Mr. Ross. Our dog is named Duke, though not a nick-name.
My last boss was Duke Newton. He was of average height, carried well the more than a few extra pounds, had a gravelly voice, and was rough as a cob. He knew his job, didn't know mine, so left me alone. We got along quite well and he pushed the company for raises that I normally would not have received. One day, and quite by chance, I learned his real first name. Huey. Duke was white.