The district duchy, also known as a district principality, was a type of state under the patrimonial system, such as a duchy or principality, formed in the feudal system as a result of a land partition between the members of a royal family. [1] It occurred in the Middle Ages and early modern period, notably in Europe, in states such as the Holy Roman Empire, [2] Duchy of Poland, [1] [3] and Kievan Rus'. [4]