Stheneboea was born into royalty, the daughter of Iobates, the king of Lycia, a kingdom on the coast of Asia Minor. She grew up in the court of her father, a place of wealth and power, and when she came of age she was married to Proetus, the king of Tiryns, a mighty fortress city in the Argolid, the plain of Argos in the Peloponnese, the peninsula of southern Greece. Proetus was a descendant of Abas, the king of Argos, and he ruled from the great citadel of Tiryns with its massive walls of Cyclopean stone, blocks so large that later Greeks believed they had been placed by giants. Stheneboea became queen of one of the most powerful cities in Greece, and for a time her life was one of ceremony and luxury. But the marriage was not a happy one, and the queen's eye began to wander.

The trouble began when Bellerophon, the grandson of Sisyphus, the wiliest king of Corinth, came to the court of Tiryns as a guest. He was young, handsome, and already famous for his lineage and his skill. Stheneboea saw him and desired him. In some accounts she made her advances openly; in others she contrived to be alone with him and declared her passion. Bellerophon, bound by the sacred laws of guest-friendship, the bond between host and guest that was older than law itself, refused her. He would not dishonour the man who had given him bread and shelter. Stheneboea, enraged by his rejection, turned her desire to vengeance. She went to her husband Proetus and told him that Bellerophon had attempted to assault her, a crime that demanded death.

Proetus was furious, but he too was bound by the laws of guest-friendship. He could not kill a man who had eaten at his table. So he devised a cunning solution. He wrote a letter to Iobates, the king of Lycia and Stheneboea's own father, sealed it, and gave it to Bellerophon to deliver. The letter contained a single command: kill the bearer. Bellerophon, innocent of the trap, set out for Lycia and delivered the letter to Iobates, who received him with hospitality for nine days before reading the message. When Iobates opened the seal, he too was bound by the same sacred law. He could not murder a guest. So he sent Bellerophon against impossible tasks, hoping that the Chimaera, the Solymi, the Amazons, and the pirates would do the killing for him. Instead, Bellerophon conquered them all, and the letter of death became the letter of his glory.

What became of Stheneboea after her accusation is told in different ways. In the earliest version, recorded by Homer in the Iliad, Bellerophon returned to Tiryns after his triumphs in Lycia, and Stheneboea, seeing that the gods favoured him, fled in fear. She threw herself into the sea and drowned, or in some accounts she was killed by Bellerophon himself in revenge. In later versions, particularly those influenced by Euripides and the tragic tradition, her story was expanded. She became a figure of pathos, a woman driven by passion to destruction, and her name was sometimes changed to Anteia, perhaps to separate the tragic heroine from the villainous queen. The change of name did not change the story: a woman who desired a hero, was rejected, and destroyed him with a lie, only to be destroyed herself when the truth came out.

Stheneboea's story was not merely a personal tragedy. It was a political one. The marriage between Proetus and Stheneboea was an alliance between Argos and Lycia, two of the great powers of the Greek world, and her accusation nearly destroyed that alliance. The letter that sent Bellerophon to Lycia was a diplomatic instrument, a way for Proetus to rid himself of a problem without breaking the laws of hospitality. The fact that Iobates, Stheneboea's own father, was the recipient shows how deeply the families were entangled. Her passion had consequences that reached across kingdoms and generations. In the end, she became a symbol of the destructive power of unrequited desire, the woman whose love turned to poison and whose lie nearly killed the greatest hero of the age.