Tisamenus, son of Orestes and Hermione (or, in one fork, Erigone), is the last Pelopid king of Argos, Mycenae, and Sparta. He inherited his father's Peloponnesian sway and fell when the Heracleidae returned to reclaim the peninsula; the victors divided his lands among Temenus, Cresphontes, and the twin sons of Aristodemus. The atlas keeps him distinct from Tisamenus son of Thersander, the Theban Epigon heir.
Adapted from Wikipedia, "Tisamenus (son of Orestes)" · CC BY-SA 4.0
I.Parentage and succession
Tisamenus was son of Orestes and Hermione, daughter of Menelaus — first cousins twice over through the Atreid and Tyndarid houses — or, in Hyginus, of Erigone daughter of Aegisthus. He succeeded Orestes to the thrones of Argos, Mycenae, and Sparta, holding the Pelopid empire at its widest.
Not to be confused with the Theban Tisamenus (tisamenus-theban), son of Thersander and Demonassa, who inherited Cadmean kingship after the Trojan War generation.
II.Fall to the Heracleidae
He was killed or driven out in the final struggle with the Heracleidae, who claimed the Peloponnese as ancestral land. After his defeat the victors divided the territories: Cresphontes took Messene, Oxylus Elis, Temenus Argos; the twin sons of Aristodemus, Eurysthenes and Procles, jointly received Sparta — the mythical origins of the Agiad and Eurypontid houses.
Pausanias has him lead defeated Achaeans into Achaia, where he died in battle — the end of Pelopid rule in the south.