Answer: Feudalism as a fundamental socio-economic relationship of the Middle Ages.
Explanation:
Feudalism implied a hierarchy in which all social classes were included, and it functioned for centuries during the Middle Ages. At the top of the "feudal pyramid" was a king who allocated land to nobles or feudal lords, on that land worked serfs who took part of the income from the land for themselves, and in case of war, the feudal lord, in turn, had to assign a certain number of soldiers. Was a larger feudal lord had to provide a larger number of majors). The disappearance of the feudal system occurred with the emergence of the first economic relations, i.e., the emergence of private property; the king no longer had to allocate land to have an army but could hire and pay from the state treasury. Fundamental changes in economic relations that are still relevant today occurred during the XIX. century. Namely, this is the Industrial Revolution period when large capitalists appear, who pay taxes to the state for their activities, and economic relations are still in force today.