Lynn White's classic study, "Medieval technology and social change", looks at three broad innovations: the stirrup, which led to mounted knights as shock troops

Lynn White's classic study, "Medieval technology and social change", looks at three broad innovations: the stirrup, which led to mounted knights as shock troops and the feudal reorganization of society to support them; the agricultural revolution driven by iron horse-drawn plows and three-field rotation; and the development and exploration of medical mechanical power and devices.