The introduction of the stirrup not only made the mounted warrior supreme in medieval warfare, but may have initiated complex and far-reaching social and cultural changes in Europe. Some scholars credit this use of the stirrup to the birth of feudalism and its subsequent spread into Northern Italy, Spain, Germany and into the Slavic territories.
One theory goes so far as to argue that the rising feudal class structure of the European Middle Ages derived ultimately from the use of stirrups:
“Few inventions have been so simple as the stirrup, but few have had so catalytic an influence on history. The requirements of the new mode of warfare which it made possible found expression in a new form of western European society dominated by an aristocracy of warriors endowed with land so that they might fight in a new and highly specialized way.”
Most scholars, however, dispute this assertion, suggesting that stirrups may provide little advantage in shock warfare, but are useful primarily in allowing a rider to lean farther to the left and right on the saddle while fighting, and simply reduce the risk of falling off. Therefore, it is argued, they are not the reason for the switch from infantry to cavalry in Medieval militaries, nor the reason for the emergence of Feudalism.
(image: taken in Metropolitan museum by haruspex)