Alcyone is one of the seven Pleiades, daughters of Atlas and the Oceanid Pleione, born on Mount Cyllene in Arcadia. By Poseidon she bore children including Hyrieus, Hyperenor, and Aethusa. She must be distinguished from Alcyone daughter of Aeolus, wife of Ceyx, and from other Alcyone homonyms.
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I.Among the Pleiades
Apollodorus lists Alcyone with Maia, Electra, Celaeno, Taygete, Sterope, and Merope as daughters of Atlas and Pleione (Bibliotheca 3.10.1). The sisters are sometimes called Atlantides or mountain nymphs of Cyllene; catasterism traditions place them as the Pleiades in the sky.
As a Pleiad she shares the collective myths of Orion's pursuit and of Zeus, Poseidon, or other gods taking several sisters as lovers.
II.Children by Poseidon
Apollodorus reports that Poseidon lay with Alcyone and that she bore Hyrieus and other offspring (including Hyperenor and Aethusa in fuller lists). Hyrieus becomes an important Boeotian eponym and father in Orion traditions.
Pausanias describes Poseidon carrying off Alcyone among the reliefs on the throne of Amyclaean Apollo (Description of Greece 3.18.10), tying her abduction to Laconian cult art.
III.Homonyms
The Aeolid Alcyone who marries Ceyx and becomes a kingfisher is a separate figure (often alcyone-aeolid in atlas data). Other minor Alcyones appear in local genealogies; the Pleiad is identified by Atlas–Pleione parentage and Poseidon’s Boeotian children.