Tchaikovsky had no experience writing ballet music for the professional theatre when he accepted Begitchev's invitation. In 1875 he began work on "Swan Lake". It was his first ballet. He studied the ballet music of other writers. He liked the music and ballets of Leo Delibes. Tchaikovsky thought Delibes's music was pretty and tuneful. Tchaikovsky however would base "Swan Lake" on a symphonic scale. Writing the music for "Swan Lake" was a way for Tchaikovsky to avoid the reality of being a homosexual in czarist Russia. Russia was a repressive state. Homosexuals were sent to prison, exiled, or banished. Symphonies did not ease the stress in the way ballet music did; he had to put too much of his inner life into symphonies. He was hired to write "Swan Lake" in May 1875. He completed the music in April 1876. The official responsible for the music at the Bolshoi Theatre thought Tchaikovsky's music impossible to understand. A "leitmotif" in Tchaikovsky's little ballet music for his nieces and nephews came to be called the "Song of the Swans". Tchaikovsky used this "leitmotif" in "Swan Lake".