In Greek mythology, several characters were known as Cycnus (Ancient Greek: Κύκνος) or Cygnus. The literal meaning of the name is "swan", and accordingly most of them ended up being transformed into swans.
According to Pseudo-Eratosthenes and Hyginus' Poetical Astronomy, the constellation Cygnus was the stellar image of the swan Zeus had transformed into in order to seduce Leda or Nemesis. Pausanias and Servius state that Apollo turned Cycnus of Liguria into a swan after the death of his lover Phaeton, then later placed him among the stars as the constellation Cygnus.