Cycnus

In Greek mythology, multiple 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.

• Cycnus, son of Ares.
• Cycnus, king of Kolonai.
• Cycnus, friend of Phaethon.
• Cycnus, son of Apollo.
• Cycnus, son of King Ederion (Ancient Greek: Ἐδερίων) or Eredion of Achaea, who, in the 6th century CE account of John Malalas, seduced Leda and made her mother of triplets: the Dioscuri and Helen. In all other sources, she had these children by Zeus who approached her in the shape of a swan (kyknos).

• Cycnus, one of the Suitors of Penelope who came from Dulichium along with other 56 wooers. He, with the other suitors, was shot dead by Odysseus with the assistance of Eumaeus, Philoetius, and Telemachus.
• Cycnus, a blunder for Guneus in the manuscript of Hyginus' Fab. 97 (list of the Achaean leaders against Troy).

The butterfly genus Cycnus is now synonymized with Panthiades.

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.