Short answers, pulled from the story.
Duke Ellington considered his Sacred Concerts the most important thing he had done. He premiered the first Sacred Concert in September 1965, creating a jazz Christian liturgy, and performed it dozens of times despite mixed reviews. Two further Sacred Concerts followed in 1968 and 1973.
Duke Ellington wrote or collaborated on more than one thousand compositions. His body of work is the largest recorded personal jazz legacy, and many of his pieces have become jazz standards.
On the 7th of July 1956, tenor saxophonist Paul Gonsalves played a 27-chorus solo during "Diminuendo and Crescendo in Blue" that drove the crowd into a frenzy and prompted Ellington to play past the festival curfew despite requests from organizer George Wein to stop. The concert became one of only five Time magazine cover stories dedicated to a jazz musician and produced the best-selling LP of Ellington's career.
Billy Strayhorn originally joined Ellington in 1939 as a lyricist and became a vital collaborator over a nearly 35-year partnership. Ellington described him as "my right arm, my left arm, all the eyes in the back of my head." Strayhorn contributed original music, arranged and polished Ellington's works, and could substitute for Duke conducting, rehearsing, or playing piano. His "Take the 'A' Train" became the band's theme in 1941.
Duke Ellington was awarded a posthumous Special Pulitzer Prize in 1999, commemorating the centennial year of his birth, in recognition of his musical genius which evoked aesthetically the principles of democracy through jazz. He had been shortlisted for the Pulitzer Prize for Music in 1965 but no prize was awarded that year.
Ellington's 1959 score for the Otto Preminger film Anatomy of a Murder was recognized by film historians as the first significant Hollywood film music by African Americans comprising non-diegetic music. The score avoided cultural stereotypes and rejected strict adherence to visuals in ways that anticipated New Wave cinema of the 1960s. Ellington appeared in the film himself, fronting a roadhouse combo.