Sisyphus is considered in Greek mythology to be the son of the Thessalian king Aiolos, the founder and king of Corinth, and the grandfather of Bellerophon.
Ino had killed Melikertes, her own son, in madness and had thrown herself into the sea with the corpse when she regained her senses. A dolphin brought the boy ashore. Sisyphus found him, buried him on the Isthmus of Corinth and, according to Pindar and others, founded the Isthmian Games in his honour, for which Theseus and Poseidon are also named as founders.
Sisyphus asked the Oracle of Delphi how he could kill his brother Salmoneus. He received the answer that he should father children with Tyro, the daughter of Salmoneus. These would then kill Salmoneus. He became involved with Tyro, and she gave birth to two sons. However, when she heard about the oracle, she killed her own children.
Autolykos secretly stole cattle, sheep and goats from Sisyphus. The latter noticed that his herds were getting smaller while those of Autolykos continued to increase. He marked his animals on their hooves and was thus able to prove the theft. He went to Autolykos to confront him. But since he did not find him, he seduced his daughter Antikleia, who shortly afterwards married Laertes and gave birth to Odysseus.
Sisyphus is called the most devious of all men; he betrayed Zeus' plans by telling the river god Asopos that it was Zeus who had kidnapped his daughter Aigina. Zeus then decided to punish Sisyphus and sent Thanatos, Death, to him. But Sisyphus overpowered him by making him drunk and putting him in such strong bonds that Death's power was broken and no one died. Only when Ares, the god of war, released Death from Sisyphus' grip (since he didn't enjoy seeing his opponents no longer dying on the battlefield) was Thanatos able to resume his duties.
Sisyphus, however, was abducted into the shadow realm by the god of war. But before Ares did so, Sisyphus forbade his wife Merope to offer him a sacrifice for the dead. When no sacrifices were offered for him, he persuaded the god of the underworld, Hades, to let him return quickly to the human world to command his wife to hold a death sacrifice for him. Back home, the cunning one enjoyed life by his wife's side and mocked the god of the underworld. But suddenly Thanatos appeared before him and brought him by force to the realm of the dead.
Sisyphus' punishment in the underworld was to roll a boulder up a steep slope. However, the stone always slipped away from him shortly before he reached the top and he always had to start over again. Today, therefore, a task that is never completed despite great effort is called Sisyphean work.
"And further I saw Sisyphus in tremendous pain: how with both arms he tried to carry away a boulder, a monstrous one. Yes, and with his hands and feet he pushed the boulder up a hill. But when he wanted to throw it over the crest, the excess weight turned it back: then anew the boulder, the shameless one, rolled down into the field. But he pushed it back again and again, straining, and the sweat ran from his limbs, and the dust rose above his head."
- Homer: Odyssey 11th canto, 593-600. translation Wolfgang Schadewaldt