The son of king Oedipus and Jocasta, Polynikes was the result of incest and cursed on his father's side. After Oedipus's death, Polynikes fought his brother Eteocles for the throne of Thebes but was driven away.
He escaped to Argos, where he made many friends. They set out to conquer Thebes, he so-called expedition of the Seven Against Thebes, and had the soothsayer Amphiaraos with him after having bribed his wife.
Thebes had a huge wall around it with seven gateways. Each warrior attacked a gate and the city almost fell. The king of Thebes hen sacrificed his life and so the Seven failed. Polynikes once again fought his brother, and in this they were both killed. The ruler of Thebes then ordered that Polynikes corpse be left to rot, but his sister Antigonedefied he king and buried her brother. For this she was buried alive.
Ten years later the Epigons (descendants) defeated Thebes as a revenge.