Aristodemus was stricken with a disease of the eye, causing King Leonidas to order him and another soldier to return home before the battle, but Eurytus turned back, though blind, and met his end charging into the fray.
Four years before the battle of Thermopylae, he is part of an ultimately unsuccessful four-man envoy sent to Rhodes to dissuade the Rhodian navy from serving Xerxes.
While at Rhodes the envoy encounters a group of Egyptian marines, led by a captain named Ptammitechus (whom they simply call 'Tommie'), and is given a tour of their warships.
Despite their refusal to surrender, Tommie presents a golden goblet as a gift to the Greeks, handing it to Aristodemos who in turn passes it to Leonidas.
A character slightly based on Aristodemus named Dilios appears in and partly narrates Frank Miller's 1998 graphic novel 300, which retells the events of the Battle of Thermopylae.