Complex sentence: By 1938 Goodman had become the King of Swing and had enough clout to integrate Carnegie Hall (nine years before Jackie Robinson entered major league baseball)--black and white jazz performers dressed in tuxedoes marched onto the stage and performed music together.
Split into simpler sentences: By 1938 Goodman had become the King of Swing and had enough clout to integrate Carnegie Hall (nine years before Jackie Robinson entered major league baseball). Black and white jazz performers dressed in tuxedoes marched onto the stage and performed jazz music together.