What was the purpose of military societies among Plains Indians?

Among the Indigenous peoples of the Great Plains, military societies served several essential functions within their communities. Primarily, these groups acted as a police force, maintaining general order and enforcing the decisions made by tribal leaders.1

Beyond their role in internal governance, these societies were often organized into secular associations that competed for battle honors, serving as a driving force for military engagement. In many tribes, such as the Hidatsa, Arapaho, Blackfoot, Mandan, and A’aninin, these groups were structured into age sets—cohorts of individuals of similar age who progressed through the system together. Membership in these societies often required the payment of initiation fees, and they played a significant role in the social and political life of the band, helping to uphold the community's structure and security.21