
Phaelos (died 424 BC) was an Athenian polemarch who served under Cleon during the Peloponnesian War. In 424 BC, Phaelos was entrusted with a key by Cleon to a chest at the Priest House in the Acropolis Sanctuary which contained sensitive information related to Cleon's plans to crush the Mytilenean revolt. The mercenary Kassandra snuck up to Phaelos as he stood guard near the Parthenon, stabbing him in the back with her spear fragment and stealing his key.