Aegiala was a daughter of Helios, the sun in Imperial myths. Her brother, Phaethon sought to reach their father and gain what he believed was his birthright. Aegiala assisted him, and when his efforts ended in tragedy, she was turned into a poplar tree for her arrogance.
Later, as a poplar, she is courted by Marko Mrnjavcevic. This story is told in the play The Courting of Aegiala.
See Aegiala for more information.