The Johanniter Order, founded in 1099 for the care of the sick and soon transformed into a religious knightly order, received substantial land grants in Western and Central Europe to support its charitable and military missions. The first Margrave of Brandenburg, Albrecht the Bear, brought the order to Altmark in 1160. From there, it significantly expanded its holdings in Brandenburg, Mecklenburg, Pomerania, and Saxony, which were administratively united in the Bailiwick of Brandenburg. During the Reformation, the order's knights converted to the Protestant faith while maintaining the independence of their corporation in close association with the Hohenzollern dynasty. The finding aid contains a rich archive of documents from the Bailiwick of Brandenburg, dating from the 15th century until its dissolution in 1811. The individual documents described within provide deep insights into the social life and cultural work of a wealthy noble community in Brandenburg-Prussia.