Parthenopaeus was persuaded to join in the war against Thebes by Adrastus. During the attack on Thebes, Parthenopaeus was the assailant on the Electran Gates, or, alternatively, the Neitian Gates. In Aeschylus' "Seven Against Thebes", he is portrayed carrying a shield with the image of Sphinx devouring the Thebans, and swearing by his spear (which for him is said to be more sacred than gods, and more precious than his own sight) to destroy the city even despite the will of Zeus. Yet according to Euripides, on the shield was depicted his mother shooting a wild boar. He was confronted by Actor at the gate.