Between the late ninth/early tenth and again in the eleventh century, English kings utilized marriage alliances, gifts, and ecclesiastical ties with northern French nobles to defend their lands against the attacks from the Northman and to enhance their wider prestige. In turn, men like Arnulf II of Flanders, Hugh the Great, and Richard I of Normandy drew upon these ties as part of their own efforts to influence regional and regnal affairs. This ‘northern’ strategy continued and became an increasingly important practice after 1066. As dukes of Normandy (and after the mid-twelfth century, rulers of Greater Anjou, Brittany, and Aquitaine), the twelfth-century English kings governed disparate states and ruled nobles who enjoyed cross-channel estates. Their counties and kingdom were not a single, unified empire or administrative unit; however, the Anglo-Norman and Angevin kings drew upon their various resources to preserve all that they had acquired. To defend their territories in France, the duke-kings made use of northern French nobles to limit the Capetian kings’ efforts to enhance their effective power and authority in the region. This northern strategy also aided the Angevin duke-kings against the alliances and assistance that Louis VII and Philip II offered to those who had disagreements with their rulers. In the twelfth-century context, the counts of Boulogne, Flanders, Guines, St Pol, and Ponthieu employed the English duke-kings’ friendship to defend their independence of action and expand their power and status. The Anglo-Norman and Angevin duke-kings used this northern strategy with notable success throughout the twelfth century; however, Philip II of France used it more effectively against John.

Building upon his father's enlistment of Flemish and Picard nobles in the 1066 conquest of England, Henry I worked throughout his reign to recruit the active support or neutrality of the northern French nobles. In 1101, he entered into an Anglo-Flemish alliance, which was renewed again in 1110. The renewal included private money fiefs to Flemish nobles as well. As Eljas Oksanen, and others, have argued, the treaty provided Henry with mercenaries and circumscribed the Flemish military contributions available to the French royal host. In 1101, it also cut off a source of aid to his brother and rival, Robert Curthose, duke of Normandy. In 1102, Henry regained the allegiance of Eustace III of Boulogne, restoring the Honour of Boulogne and negotiating his marriage to Mary of Scotland, Henry's sister-in-law.