The Republic of St. Peter seeks to reclaim for central Italy an important part of its own history. Noble's thesis is at once original and controversial: that the Republic, an independent political entity, was in existence by the 730s and was not a creation of the Franks in the 750s. Noble examines the political, economic, and religious problems that impelled the central Italians—and a succession of resolute popes—to seek emancipation from the Byzantine Empire. He delineates the social structures and historical traditions that produced a distinctive political society, describes the complete governmental apparatus of the Republic, and provides a comprehensive assessment of the Franco-papal alliance.

The richest and most politically complex regions in Italy in the earliest middle ages were the Byzantine sections of the peninsula, thanks to their links with the most coherent early medieval state, the Byzantine empire. This comparative study of the histories of Rome, Ravenna, and Venice examines their common Byzantine past, since all three escaped incorporation into the Lombard kingdom in the late 7th and early 8th centuries. By 750, however, Rome and Ravenna's political links with the Byzantine Empire had been irrevocably severed. Thus, did these cities remain socially and culturally heirs of Byzantium? How did their political structures, social organisation, material culture, and identities change? Did they become part of the Western political and ideological framework of Italy? This study identifies and analyses the ways in which each of these cities preserved the structures of the Late Antique social and cultural world; or in which they adapted each and every element available to them to their own needs, at various times and in various ways, to create a new identity based partly on their Roman heritage and partly on their growing integration with the rest of medieval Italy. It tells a story which encompasses the main contemporary narratives, documentary evidence, recent archaeological discoveries, and discussions on art history; it follows the markers of status and identity through titles, names, ethnic groups, liturgy and ritual, foundation myths, representations, symbols, and topographies of power to shed light on a relatively little known area of early medieval Italian history.