His two brothers were the playwright Aeschylus and Ameinias, hero of the battle of Salamis, while his sister was Philopatho (Greek: Φιλοπαθώ), the mother of the Athenian tragic poet Philokles.

[1] In 490 BC, Cynegeirus and his brothers Aeschylus and Ameinias fought to defend Athens against Darius's invading Persian army at the Battle of Marathon.

Here the hero, having successively lost both his hands, hangs on by his teeth, and even in his mutilated state fought desperately with the last mentioned weapons, "like a rabid wild beast!

[7] There was a custom in Athens that the father of the man who had the most valorous death in a battle should pronounce the funerary oration in public.

The incident of the heroic death of Cynaegeirus became an emblem of cultural memory in ancient Greece and was described in literature in order to inspire patriotic feelings to future generations.