 After Christianity became established in Argos, the first bishop documented in extant written records is Genethlius, who in 448 AD took part in the synod called by Archbishop Flavian of Constantinople that deposed Eutyches from his priestly office and excommunicated him.The next bishop of Argos, Onesimus, was at the 451 Council of Chalcedon.His successor, Thales, was a signatory of the letter that the bishops of the Roman province of Hellas sent in 458 to Byzantine Emperor Leo I the Thracian to protest about the killing of Proterius of Alexandria.