The author studies selected fundamental literary records from Great Moravia of the 9th century (The rules of the holy fathers [Zapovědi svatych otcov], Judicial law for laymen [Zakon sudnyj ljudem], Nomocanon [Nomokanon], Adhortation to rulers [Vladykam zemle Božie slovo velit]) presumably compiled, translated or created by Constantine (Cyril) and Methodius, the Thessaloniki brothers. In the context of defining early and medieval Christian ethics, the author concluded that the texts in question contain elements of the Christian code of ethics, by means (...) of which Constantine (Cyril) and Methodius, following the model of the Byzantine Emperors Leo III and Constantine V, wished to form the social morality of Great Moravia. Based on this, the author holds the opinion that the history of Christian ethics in Moravia, Slovakia and Bohemia goes as far back as the activities of Constantine (Cyril) and Methodius and the period of Great Moravia. (shrink)