I'm glad you mentioned that Buddha and Epictetus are among the "ancestors" of cognitive therapy. Buddha of course is well enough known to have had a major religion named after him. Epictetus, though, is comparatively unsung -- even though he had a powerful influence on his contemporaries of about 2,000 years ago (e.g., the Emperor Marcus Aurelius), and the term "Stoic" and its derivatives have long been part of everyday speech.
One of these days when I have a little more time I think I'll post a blurb on Epictetus and the later (Roman) Stoics. Since the old-time classical education has gone the way of the dodo, I take a certain pleasure in bringing to people's attention that some of the world's best ideas were around long before us. Just for a preview: most people think of Stoicism as white-knuckles-in-the dentist's-chair. Uh-uh. That's not the point at all. More to come . . . .