ASCAP (American Society of Composers and Publishers) raised their broadcasting fees in 1940
This made it very expensive to play live recordings over the radio (compositions by ASCAP members - Ellington was a member)
Most radios hired bands to perform live over the air to broadcast to a jazz hungry audience
Strayhorn, a non-ASCAP member, was playing in Ellington's band at the time and composed this as The Duke Ellington Orchestra's new "signature" jazz chart
Duke Ellington is considered one of America's best composers (he wrote over 1000 compositions)
Billy Strayhorn collaborated with Duke Ellington for almost 30 years
Duke Ellington's band was a symbol of racial equality - it toured around the country with both black and white jazz performers
That is Duke Ellington playing the opening piano solo in this video clip
The Duke Ellington Orchestra still tours the world to this day
after Duke's death, Mercer Ellington (his son) took over as bandleader and it is currently being led by Paul Ellington