<P> "Then (Apollon) gave him (Sarpedon) into the charge of swift messengers to carry him, of Hypnos and Thanatos, who are twin brothers, and these two presently laid him down within the rich countryside of broad Lycia ." </P> <P> Counted among Thanatos' siblings were other negative personifications such as Geras (Old Age), Oizys (Suffering), Moros (Doom), Apate (Deception), Momus (Blame), Eris (Strife), Nemesis (Retribution) and even the Acherousian / Stygian boatman Charon . Thanatos was loosely associated with the three Moirai (for Hesiod, also daughters of Night), particularly Atropos, who was a goddess of death in her own right . He is also occasionally specified as being exclusive to peaceful death, while the bloodthirsty Keres embodied violent death . His duties as a Guide of the Dead were sometimes superseded by Hermes Psychopompos . Conversely, Thanatos may have originated as a mere aspect of Hermes before later becoming distinct from him . </P> <P> The god's character is established by Hesiod in the following passage of the Theogony: </P> <P> And there the children of dark Night have their dwellings, Sleep and Death, awful gods . The glowing Sun never looks upon them with his beams, neither as he goes up into heaven, nor as he comes down from heaven . And the former of them roams peacefully over the earth and the sea's broad back and is kindly to men; but the other has a heart of iron, and his spirit within him is pitiless as bronze: whomsoever of men he has once seized he holds fast: and he is hateful even to the deathless gods . </P>

Who was the first person to say sleep is the cousin of death