Once Upon a Time it was believed that as a consequence of its astounding beauty, the Swan was struck mute for life; but at their final hour sang a song of unsurpassed loveliness and elegance.
Pliny the Elder finally refuted this legend in his Natural History, AD 77: "Observation shows that the story that the dying swan sings is false."
It is a poetic notion that has proven useful for many years. Chaucer used it, as did Shakespeare.
Samuel Taylor Coleridge wrote in his poem 'On a Volunteer Singer':
"Swans sing before they die; ’twere no bad thing
Did certain persons die before they sing."