This paper will examine memories of a fourth‐ to fifth‐century western Balkan past in Justinian's Novella 11. Announcing the appointment of a new northern Illyrian archbishop at the city of Justiniana Prima, this decree refers nostalgically to an earlier period of late antiquity, prior to the invasions of Attila, when Sirmium, rather than Justiniana Prima, had been the administrative and ecclesiastical capital of Illyricum. Published in April 535, on the eve of the Gothic War, it thus suggested that Gothic‐held Sirmium belonged to the eastern Roman state. In this way it contradicted rival political propaganda emanating from the Gothic kingdom of Italy, according to which it was the rightful Roman heir to the western Balkans.