During the Peloponnesian War Galeos supplied slaves to whoever required them, setting his headquarters within ruins on the eastern shore of Lake Kopais. However, during one of his expeditions, Galeos and his retinue were attacked by bears south of the Snake Head Rock.
The timely arrival of the Spartan misthios Kassandra spared Galeos' life, though she was too late to save his companions. Taking him to be treated by the physician Hippokrates in the polis Thebes nearby, Kassadra learned of Galeos' occupation. Hippokrates was loathe to treat Galeos, but agreed to do so if Kassandra saved Galeos' victims.