Complex sentence: Ellington retired shortly after the start of World War II, on 4 April 1940, and died on 13 June 1967 from coronary thrombosis at Scio House Hospital in London.
Split into simpler sentences: Ellington retired shortly after the start of World War II, on 4 April 1940. He died on 13 June 1967 from coronary thrombosis at Scio House Hospital in London.