Mycenaean tholos tombs that betokened a grander past, were often the site of hero-cults. Not all heroes were even known by names. Aside from the epic tradition, which featured the heroes alive and in action rather than as objects of cultus, the earliest written reference to hero-cult is attributed to Dracon, the Athenian lawgiver of the late seventh century BC, who prescribed that gods and local heroes should both be honoured according to ancestral custom. The custom, then, was already established, and there were multiple local heroes. The written sources emphasise the importance of heroes' tombs and the temenos or sanctuary, where chthonic rites appeased their spirits and induced them to continue to favour the people who looked to them as founders, of whom founding myths were related. In the hero's restricted and local scope he "retained the limited and partisan interests of his mortal life. He would help those who lived in the vicinity of his tomb or who belonged to the tribe of which he himself was the founder," observes Robert Parker, with the reservation that Heracles, with his pan-Hellenic scope, was again the exception. Whitley interpreted the final stage, in which hero-cult was co-opted by the city-state as a political gesture, in the archaic aristocratic tumulus surrounded by stelae, erected by Athens to the cremated citizen-heroes of Marathon (490 BC), to whom chthonic cult was dedicated, as the offering trenches indicate. On the other hand, Greek heroes were distinct from the Roman cult of dead emperors, because the hero was not thought of as having ascended to Olympus or become a god: he was beneath the earth, and his power purely local. For this reason hero cults were chthonic in nature, and their rituals more closely resembled those for Hecate and Persephone than those for Zeus and Apollo: libations in the dark hours, sacrifices that were not shared by the living. Two exceptions to the above were Heracles and Asclepius, who might be honored as either heroes or gods, with chthonic libation or with burnt sacrifice. Heroes in cult behaved very differently from heroes in myth. They might appear indifferently as men or as snakes, and they seldom appeared unless angered. A Pythagorean saying advises not to eat food that has fallen on the floor, because "it belongs to the heroes". Heroes if ignored or left unappeased could turn malicious: in a fragmentary play by Aristophanes, a