a labor force subjected to systematic exploitation.
Prelotta, Adrian knew, intended to change that. The other Southron tribes had joined this great invasion for the customary reasons—loot, and the prospect of "martial glory." Only Prelotta was thinking further ahead than that. He intended to occupy this territory, and remain there after the other tribes returned south for the winter. Prelotta was thinking like a conqueror, not a raider—and for that, he needed a subject labor force.
Helga was still glaring at him. Adrian tried to think of what he might say to mollify her, but the only words which came to him were . . . best left unspoken.
This is really no different