The Commissary of War in the Thirty Years' War presents itself as an object worthy of investigation with regard to its role of controlling free mercenary troops and thus enhancing power of princes in the Early Modern Europe. Focusing on the Bavarian Army, one of the best organized military forces in this era, this work sheds light on the activities of the commissaries that had been observed only from the normative perspective in hitherto studies. Analysis of primary sources such as military administration documents and private correspondence will show the entanglement of various competences and the functions of the social network for the commission holders in service. As a result, this work provides proof of the complexity of rulership in the Early Modern Europe.