Pyotr Illyich Tchaikovsky (1840-1893) was a Russian composer of the romantic period. He composed a solemn overture, called the '1812 Overture'. Composed in 1880, it memorialized the successful defense of Russia against Napoleon's invading 'Grand Armee'. It debuted in Moscow on August 20, 1882 under a tent near the unfinished Cathedral of Christ the Savior. The 15 minute overture is a festival overture, best known for its climatic volley of 16 canon firings, ringing chimes, and brass fanfare finale.

The piece begins with a simple Russian melody of the Eastern Orthodox hymn 'of the Holy Cross' (also known as 'O Lord, Save Thy People'). This represents the Russian people praying for a swift conclusion to the French invasion.

Then, the French National anthem, called 'La Marseillaise' is heard, representing the invading French army. This competes against Russian folk music as the French army approaches Moscow. At this point, 5 canon shots are heard representing the Battle of Borodino, one of the deadliest days of the Napoleonic Wars. This is when the French army seems to be winning.

After a long descending run, representing the French army retreating out of Moscow, the grand finale culminates with 11 more canons and the melody of 'God Save the Tsars', the national anthem of the Russian Empire. A total of 16 canons firings in all.

More Info: en.wikipedia.org