Aethusa

About

In Greek mythology, Aethusa was a daughter of Poseidon and the Pleiad Alcyone, daughter of Atlas. She was loved by Apollo and bore to him Eleuther and Linus. Through either of the latter two, Aethusa became the grandmother of Pierus, father of Oeagrus, father of the musician Orpheus. Because of this genealogical fact, she was usually identified as a Thracian.

Summary from Wikipedia