Who was Prince Stash?

Prince Stash sits on the floor during a session.

Prince Stash Says: You can see Ringo Starr on the left, me facing the camera, the back of George Harrison's head in the middle, and John Lennon smoking a cigarette on the right. Paul McCartney is somewhere in the room, but he's out of frame. 

 

During that time in 1967, when Jane Asher was touring the United States as Juliet in Romeo and Juliet, and Paul McCartney was living at 7 Cavendish, leading a bachelor's life, a variety of people came and went from his life. 

One of those people was  Price Stanislas Klossowski de Rola, also known as Prince Stash.  He, along with an artist named Dudley Edward, moved in with Paul in January 1967.  Prince Stash recalls what he calls a "harem" of girls being available, as well as a group of fans always outside the gates. 

Dudley and Stash painted a mural while they were at Paul's home, and apparently, they were with Paul at the Bag O'Nails Club the night he met Linda.  

Prince Stash says that he recorded with the Beatles on "You Know My Name (Look Up the Number)"
 and maybe "Baby You're a Rich Man" (He doesn't remember).   

We know that Prince Stash visited the studio a few times with the Beatles, as evidenced by photos, and we also know that he stayed with Paul.  However, much of what he says online is thought to be exaggerated.  Some of his information doesn't match up in terms of dates.  He isn't someone you find mentioned in Beatles biographies, except for a few Paul McCartney biographies.