The Great Stirrup Controversy is a controversy about the Stirrup Thesis, the theory that feudalism in Europe was largely the result of the introduction of the stirrup to cavalry.
The idea, first proposed by Lynn White Jr. in 1962, contends that as mounted warfare became easier and more effective for Frankish cavalry, they replaced infantry as the most powerful force on the battlefield, and thus aristocracy with wealth enough to own a horse became the dominant force on the battlefield, and thus were in a position to offer protection to horseless peasants.
It is agreed that cavalry replaced infantry in Carolingian France as the preferred mode of combat around the same time that feudalism emerged in that area, but whether this shift to cavalry was caused by the introduction of the stirrup is a contentious issue among historians. It has been asserted that armored cavalry were used successfully without stirrups before their introduction, and that the transition to cavalry was not a result of new technologies.
Modern reenactment and experimental archaeology has, however, shown that stirrup provides very little benefit for a mounted lancer, and a cantled saddle and spurs have a greater effect. Stirrups provide stability for striking in melee after the initial cavalry charge.
The first fully armoured cataphracts appeared in third century BC, almost 1000 years before the Carolingian dynasty.