
Hypnos is one of the many children of Nyx (Night) and the twin brother of Thanatos (Death). Hypnos enters the sleep of mortals and, at the bidding of the Olympians, gives them dreams of foolishness or inspiration, depending on the individual and their divine protectors or enemies.
Hypnos is husband to Pasithea, one of the Graces, because he did a very dangerous favor for Hera. During the Trojan War, Hera wanted to distract Zeus from the battle so she could assist the Achaeans (Achaians), who seemed to be losing the war. She wanted Hypnos to cast a spell of sleep on Zeus but he refused. At first Hera offered Hypnos a golden throne crafted by her son Hephaistos (Hephaestus) but she was forced to raise the ante when Hypnos reminded her of the only time he had dared cast sleep on Zeus. Long before the Trojan War, Hera was angry at Herakles (Heracles) and she had persuaded Hypnos to make Zeus sleep while she tormented the hero. When Zeus awoke, he was in a rage. He searched for Hypnos and finally found him hiding in the arms of his mother, Nyx (Night). Zeus overcame his anger and simply warned Hypnos not to try such a trick again, and Hypnos went unpunished.
In preparation for this new deception, Hypnos made Hera swear oaths of her sincerity. He agreed to help her deceive Zeus for the hand of one of the Graces, Pasithea. He turned himself into a bird and, before Zeus could see him, hid in the tops of the trees on Mount Ida. He stayed hidden until Hera had seduced Zeus. When the father of gods was dulled by pleasure and sleep, Hypnos flew to Poseidon (lord of the Sea) and urged him to increase his efforts in helping the Achaeans because Zeus was asleep and unaware of the Earth Shaker’s meddling. Poseidon strode through the ranks of soldiers and urged them on. Finally, his bellowing and screeching roused Zeus from his slumber but, in that short time, the Achaeans had turned the battle back on the Trojans. Hera’s trick had worked. Zeus never found out that Hypnos had betrayed him (again).
When Zeus’ son, Sarpedon, was killed at Troy, Zeus commanded Hypnos and Thanatos to retrieve him from the dirt and grime of the battlefield and return the cleansed body of his fallen son to his home in Lykia (Lycia).
The line numbers listed here correspond fairly well with the Lattimore and Murray/Wyatt translations of The Iliad. Other translations (Fitzgerald, Fagles et al) do not correspond as well but, with a small amount of effort, you should be able to find the reference you need regardless of the translation you use. Lattimore (ISBN 0226469409); A.T. Murray/William F. Wyatt Vol. I & II (ISBN 0674995791 and 0674995805); Robert Fitzgerald (ISBN 0374529051); Robert Fagles (ISBN 0140275363)