While the most famous Helen in mythology was "Helen of Troy she is not the only one. Helen was the daughter of Klytemnestra and Aegisthus. After those two murdered AgamemnonKlytemnestra and her lover Aegisthus murdered Agamemnon, Helen's half-sister Elektra helped Helen's half-brother Orestes escape thus saving him. Orestes would return and along with Elektra, they killed Helen's parents in revenge and killed the infant Helen to boot.
Klytemnestra & Aegisthus