See biographies by C. Felsenthal (1981) and D. T. Critchlow (2005).
Phyllis is a character in Greek mythology. Daughter of Lycurgus, King of Thrace, she married Demophon, King of Athens and son of Theseus, while he stopped in Thrace on his journey home from the Trojan war.
Demophon, duty bound to Greece, returns home to help his father, leaving Phyllis behind. She sends him away with a coffin with the sacrament of Rhea, asking him to open it only when he has given up hope of returning to her. From here, the story diverges. In one version, Phyllis commits suicide by hanging herself from a tree. Where she is buried, an almond tree grows, which blossoms when Demophon returns to her. In a second version of the story, Demophon opens the caskets and accidentally falls on his own sword.
The Nine Ways is derived from the story of Phyllis, who is said to have returned nine times to the shores to wait for Demophon's return.
Fulkerson, Laurel. "Reading dangerously: Phyllis, Dido, Ariadne, and Medea". The Ovidian Heroine as Author. Cambridge: Cambridge University Press, 2005.