The Bavarians soon came under the dominion of the Franks, probably without a serious struggle. The Franks regarded this border area as a buffer zone against peoples to the east, such as the Avars and the Slavs, and as a source of manpower for the army. Sometime around 550 AD they put it under the administration of a duke - possibly Frankish or possibly chosen from amongst the local leading families - who was supposed to act as a regional governor for the Frankish king.