Conversation so far:
What happened to Duke Ellington during the later 1930's?
From 1936, Duke Ellington began to make recordings with smaller groups and he composed pieces intended to feature a specific instrumentalist.
Why did Duke Ellington leave Irving Mills?
Duke Ellington left to sign on with the William Morris Agency.

Question: How did his father die?
Self-contained rewrite: How did Duke Ellington father die?