We talked about Tchaikovsky (pronounced "chie-KOFF-skee") in July 2009. Here is another of his great masterpieces. Tchaikovsky himself would refer to this pieces as his "Russo-Serbian March". It is formally known as Slavonic March in B-flat Minor, Op. 31, but it is most well known by its French title: Marche Slave (pronounced "marsh slahv").
Marche Slave was written in 1876. At this time, the expanding Ottoman Empire (mostly modern Turkey) was at war with Serbia. Russia supported Serbia, and the government requested a march dedicated to the Serbian effort.
The main theme of Marche Slave is from a Serbian folk song, whose title in English is "Come, my dearest, why so sad this morning?". This theme can be heard here: