We do know that Tchaikovsky had much control over the stories content. He and his colleagues both agreed that the swan represented womanhood in its purest form. The stories and legends of swan-maidens date as far back as ancient Greece; when the Greek god Apollos was born, flying swans circled above their heads. Legends of swan maidens can also be found in The Tales of the Thousand and One Nights, Sweet Mikhail Ivanovich the Rover and The Legend of the Children of Lir.
Swan Lake is known for its demanding technical skills all because of one extremely gifted ballerina, Pierina Legnani. She performed with such grace and discipline, the audience and everyone else who saw her claimed she set the bar. Every girl to dance the part of Odette/Odile after her was compared to Legnani's performance. Legnani performed 32 fouettes (a fast whipping turn on one foot) in a row a move many ballerinas resent because of its extreme difficulty. However, Swan Lake remains a favorite for many girls because of its extreme difficulty; technically and emotionally. The prestige that comes with performing Swan Lake flawlessly is invaluable.