Sharing a song that one of my kids performed recently and another that she is still rehearsing. The former, "Instant Concert," contains bits of 30 songs. Before my daughter's band played "Instant Concert," the conductor said she would give a free cd to anyone who could name all 30 songs. I don't think anyone won it!
Tchaikovsky Research says: "The [Slavonic] March was commissioned by the director of the Russian Musical Society, Nikolay Rubinstein, for a concert in aid of victims of the conflict between Serbia and Turkey. Tchaikovsky received the request around 20 September 1876, and the completed full score is dated 25 September." 5 days!!!