The phrase swan song has an ancient origin. The ancient Greeks believed that the swan had a special gift to sing most beautifully before death. The song of the dying swan was believed to be extremely passionate and beautiful, overwhelmed with the joy of a being who sees glory in another life. In Greek mythology, the swan was a bird consecrated to Apollo, and it was therefore considered a symbol of harmony and beauty, and his limited capabilities as a singer were sublimated to those of songbirds. Aesop's fable The Swan and the Goose incorporates the swan song legend as saving his life when he was caught by mistake instead of the goose but was recognized by his song. In the tragedy Agamemnon by Aeschylus, Clytemnestra compares the dead Cassandra to a swan who has "sung her last final lament". Plato's Phaedo records Socrates saying that, although swans sing in early life, they do not do so as beautifully as before they die. Aristotle noted in his History of Animals that swans "are musical, and sing chiefly at the approach of death".
Roman poet Ovid mentions swan song in The Story of Picus and Canens in Metamorphoses: "There, she poured out her words of grief, tearfully, in faint tones, in harmony with sadness, just as the swan sings once, in dying, its own funeral song." The swan was also described as a singer in the works of the Roman poets Virgil and Martial.
The legendary swan song symbolizes music and poetry, especially one that is divinely inspired, passionate or tragic. The song of the swan of Christ is described in the Gospel of John 14-17.
The story of the swan's last poem has found a place in the works of many writers and poets. William Shakespeare used it in several plays. In Merchant of Venice, Portia says: "Let music sound while he doth make his choice; / Then, if he lose, he makes a swan-like end, / Fading in music." Similarly, in Othello, the dying Emilia exclaims: "I will play the swan, / And die in music." The poet Samuel Taylor Coleridge turned the phrase on his head in the poem On a Volunteer Singer:
"Swans sing before they die; 'twere no bad thing / Did certain persons die before they sing."
The swan song was an inspiration to many painters. Leonardo da Vinci noted: "The swan is white without spot, and it sings sweetly as it dies, that song ending its life."
The famous Finnish composer Jean Sibelius, as a thirty-year-old, composed his famous work, The Swan of Tuonela, in 1895. This legend for orchestra, Sibelius composed inspired by legends from the Finnish folk epic Kalevala. The performance of the song of the dying swan in this part is fascinating. Also, there are known the cycles of solo songs Swan Song, by the famous Austrian composer Franz Schubert. These were the last poems of Franz Schubert and were published after his death, in 1828.