Maximus Ultimus Mostimus
In real life, his name was Vinny (the Chin) Gigante.
That's the guy.
1992, Gigante was officially recognized as the most powerful crime boss in the United States. Dubbed "The Oddfather" and "The Enigma in the Bathrobe" by the press, Gigante often wandered the streets of Greenwich Village in his bathrobe and slippers, mumbling incoherently to himself, in what Gigante later admitted was an elaborate act to avoid prosecution. The act worked for over 10 years and Gigante was determined to be mentally unfit to stand trial. However, by 1997 he was tried and convicted of racketeering and was given a 12 year sentence. He died while in prison in 2005 at the United States Medical Center for Federal Prisoners.