The article deals with the main types of social and military relations between the indigenous people and the new landlords that formed in the times of building and reinforcing the rule of the Teutonic Order in Warmia, a part of Prussia. These included military action and the military obligations of the indigenous people and their descendants in the 13th and 14th centuries. The issue is discussed in the context of the family ties of the Old Prussians. In the era of the conquest, and when building the territory of the Teutonic Order in Prussia, family rule over possessions was reinforced at the expense of other social relations. From the article, it is clear that the military potential of the Diocese of Warmia was supported mainly by the indigenous people, who were granted Kulm law and received other privileges. It also seems that Old Prussians not only fought alongside the Order (knights of the Old Prussian origin, small freemen, equites Prutheni), but also led the army of the diocese as bishopric vogts.