I think the following is well worth taking on board on the details of warfare in Frankish lands ~ Please see
https://erenow.net/ww/medieval-warfare-a-history/2.php
PART I PHASES OF MEDIEVAL WARFARE.
PART 2 CAROLINGIAN AND OTTONIAN WARFARE.
Quote"WARFARE was perhaps the most dominant concern of the political elites of the eighth, ninth, and tenth centuries. Other medieval social orders have been described as ‘a society organized for war’: Carolingian and Ottonian societies were largely organized by war. The political community, when it came together, was often called ‘the army’ even when it was not functioning as one. And usually it did come together in order to function as one. Massive coercive force was repeatedly deployed against subordinate peoples on the frontiers, with considerable success. It was also deployed, with less consistent success, against invading predators—Northmen (Vikings) along the Atlantic and North Sea coastlines from the early ninth century, Muslims along the Mediterranean coastline from the last years of the eighth century, Magyars from the Danube valley from the last years of the ninth century. And of course it was deployed against rivals within the Frankish world, by both rulers and magnates. Its deployment required substantial investment in organization (taxation and other forms of funding, transport, command structures), physical resources (food, water, equipment), and manpower (conscripted and ‘voluntary’). Increasingly also investment in defensive fortifications was required. Success in warfare brought prestige, authority, and power beyond the immediate results of the campaigning itself; failure similarly risked a crisis in the legitimacy and stability of political authority. "Unquote.