The name, Pleiades, comes from Ancient Greek: Πλειάδες. It probably derives from plein ("to sail") because of the cluster's importance in delimiting the sailing season in the Mediterranean Sea: "the season of navigation began with their heliacal rising". In Classical Greek mythology the name was used for seven divine sisters called the Pleiades. In time, the name was said to be derived from that of a mythical mother, Pleione, effectively meaning "daughters of Pleione". In reality, the ancient name of the star cluster related to sailing almost certainly came first in the culture, naming of a relationship to the sister deities followed, and eventually appearing in later myths, to interpret the group name, a mother, Pleione.