Rome and the heritage of ancient Illyricum in the ninth century *

Papal intervention often failed to produce the hoped-for results. It was regarded as unwelcome by authorities who were keen to impose their own hegemony over post-Avar Illyricum. The rhetorical 'Illyricum heritage' argument was the basis for legitimizing papal intervention in Danubian Europe and the Balkan Peninsula in the second half of the ninth century. Hadrian does not name the geographic regions over which he wants to reassert papal jurisdiction, either in his letter to the Byzantine emperors or in his letter to Charlemagne. He merely refers to all those ecclesiastical provinces, which had been seized during the iconoclasm crisis. However, Hadrian did not always exclude Illyricum, and elsewhere he includes the Greek provinces of Illyricum as coming under Roman jurisdiction. Finally, the Council of Nicaea was an opportunity for the papacy to recover an important international diplomatic role.