Halcyon was the daughter of Aelous, who controlled the winds in Greece. She was married to Ceyx, the king of Tachis. They were deeply in love, but had a habit of teasing each other and calling each other Hera and Zeus.
While Halcyon was a goddess, Ceyx was mortal and the gods decided to have their revenge. Ceyx decided to sail to Delphi against Halcyon’s wishes and concerns. Her concerns were not in vain; Ceyx was drowned in a storm on the way to Delphi. However before he drowned he asked Poseidon to ensure that his body made it back to Halcyon. At the same point, Halcyon was begging Hera to ensure that he had a safe trip.
Hera was too late however and asked Hypnos to send a dream to Halcyon telling her what had happened to her husband. Upon receiving the dream, Halcyon rushed to the shore where she found her husband’s body and threw herself into the waves. Zeus, touched by her devotion, turned them both into halcyons-the creation of the birds.
The myth doesn’t end there, however. Zeus ruled that the birds would only lay their eggs in winter. The winter storms kept washing away the nest and destroying the eggs. Halcyon started crying to Zeus for pity and finally he relented. He gave her seven days of calm before and after the winter solstice for nesting. Those days are still calm, and are still called Halcyon Days.