Hyllus
Hyllos
Eldest son of Heracles by Deianira, leader of the Heraclidae in the generation immediately after his father's deification. When Eurystheus of Mycenae demanded their surrender from King Ceyx of Trachis, Hyllus led the family south to Athens where they took sanctuary under Demophon son of Theseus (Apollodorus *Bibliotheca* 2.8.1; Euripides *Heraclidae*). In the battle against the pursuing Mycenaean army he chased the fleeing Eurystheus to the Scironian cliffs above Megara and killed him there (Apollod. 2.8.1 — cutting off his head on the cliffs; Eur. *Heracl.* 928–1055 keeps Eurystheus alive for trial at Athens). Marrying Iole — the Oechalian princess his father had won — he led a first premature invasion of the Peloponnese and was killed in single combat at the Isthmus by Echemus son of Aeropus, king of Tegea, the outcome binding the Heraclidae to a generation's withdrawal (Herodotus 9.26 — the Tegean envoys' speech at Plataea is the canonical source; Pausanias 8.5.1 still pointed out Echemus's tomb at Tegea in the second century AD). Apollodorus 2.8.2 has a minority version in which Hyllus is killed by Orestes's son Tisamenus instead of by Echemus.
Origin
Eldest son of Heracles and Deianira (Apollod. 2.7.8 + 2.8.1); first-generation leader of the Heraclid return; killed in single combat at the Isthmus by Echemus of Tegea (Hdt. 9.26).