The Stirrup Thesis

The stirrup thesis holds that the introduction of the stirrup to Frankish cavalry in the eighth century enabled mounted shock combat — the couched-lance charge that channeled the kinetic energy of horse-and-rider through a single point of contact. The expense of sustaining a mounted warrior class (warhorse, armor, years of training) required new economic arrangements, and the institutional solution that emerged was feudalism: land grants supporting warriors whose labor the peasant class funded. White did not claim the stirrup caused feudalism. He claimed it changed the landscape of possibility in ways that made feudal arrangements dramatically advantageous — and therefore likely — in the competitive environment of early medieval Europe.