Simplify the following text for a Grade 9 native English-speaking person.
Original: Very well known is the one time the Erinyes followed Orestes : Orestes ' mother Klytaimnestra and her lover Aegisthos had killed Orestes ' father Agamemnon .
Simplified: Orestes killed Clytemnestra to avenge the murder of his father , Agamemnon . The Erinyes chase Orestes to Athens where Athena then intervenes .