Tchaikovsky wrote Marche Slav in 1876 for a charity concert to support a war effort in the Balkans. He composed and fully scored the march in the short time of just 5 days. (Quick for anyone, but amazing for Tchaikovsky) The themes are loosely based on three Serbian folk songs, each with a quite different character, and it aisc incorporates the Russian national anthem. At the first performance its impact was such that it had to be encored in full, receiving a tumultuous reception - twice!