Brittany, as a political unit, was a creation of the Carolingian empire, but during the tenth and the first half of the eleventh centuries, the former Carolingian regnum experienced political fragmentation. Although individuals vied for the title of ‘dux Britannie’, in fact none exercised authority over the whole of the Armorican peninsula and its hinterland. By the mid-eleventh century, the peninsula was divided into six main political units; the county of Rennes, the lordships of Penthièvre and Léon, the county of Cornouaille, the Broërec (or the Vannetais) and the county of Nantes (see map 1).

At this point, the process of political fragmentation was halted by a series of marriages which united the comital families of Rennes, Nantes and Cornouaille to form a single ducal dynasty. Duke Hoël I (1066–84) and his descendants now had the potential to consolidate ducal authority, winning back the exercise of public authority from those who had usurped it. This chapter will present a brief survey of political conditions in Brittany for the 100 years from 1066 to the advent of Henry II from the perspective of ducal authority.

Around 1066, the position of the dukes of Brittany was analogous to that of the contemporary kings of France, the first among equals, having prestige and no internal rival for the ducal title, but no real authority outside their own domains. In terms of the exercise of ducal authority, three different categories of territory may be identified.