This paper draws attention to the twelfth-century French romance Partonopeus de Blois and its author's original use of the name ‘Byzantium’ instead of conventional ‘Greek’ or ‘Constantinopolitan Empire’. It investigates roots of the modern-day belief that the term has been applied as a designation of the medieval state only since the sixteenth century. A linguistic and literary analysis challenges the premise and explores possible scenarios of the name's introduction into the Old French text. A suggested interpretation de-emphasizes the popular east-west ideological context in favour of simpler story-telling concerns.