Conversation so far:
What happened during the later 1930's?
From 1936, Ellington began to make recordings with smaller groups (sextets, octets, and nonets.
Are there any other interesting aspects about this article?
After leaving agent Irving Mills, he signed on with the William Morris Agency.
Why did he leave Irving Mills?
In the summer of that year, his father died, and due to many expenses, Ellington's finances were tight.
How did his father die?
CANNOTANSWER.

Question: Was he successful with his new agency?
Self-contained rewrite: Was Ellington  successful with  William Morris Agency?