Upon his return from the Trojan War, Agamemnon, king of Mycenae, is killed by his wife Clytemnestra. Their daughter, Elektra sends her brother Orestes into exile to protect him. According to Aeschylus' version in the 'Choephoroi', the second play in the Oresteia trilogy, many years later Clytemnestra, troubled by dreams, sends Elektra to Agamemnon's tomb to pour libations. There she meets her brother who had come to dedicate a lock of hair. Once the siblings are reunited they plot to avenge their father's death, which Apollo had ordered Orestes to carry out.
The recognition scene from the 'Choephoroi' inspired many South Italian vase-painters. For a hydria by Python with a similar scene, see A. D. Trendall, The Red-figured Vases of Paestum, Rome, 1987, p. 149, no. 250.