WATCHMAN, under instructions from Clytemnestra
CLYTEMNESTRA, wife of king Agamemnon, left at home while he is away fighting at Troy
HERALD, sent home with news in advance of the victorious Agamemnon
AGAMEMNON, king of Argos, son of Atreus, joint leader with Menelaus of the expedition against Troy
CASSANDRA, beautiful daughter of Priam, king of Troy, endowed by Apollo as a prophetess, brought back as a slave by Agamemnon
AEGISTHUS, lover of Clytemnestra, son of Thyestes, who was the brother of Atreus, with a grudge against him
CHORUS, elders of the city of Argos
[PLACE: In front of the palace at Argos, ancestral seat of AGAMEMNON and his brother Menelaus.]