<Li> Jump up ^ Hägermann & Schneider 1997, pp. 425f . </Li> <Li> Jump up ^ White, Jr. 1962, p. 111 </Li> <Li> Jump up ^ Di Ieva 2007, pp. 1--4 </Li> <Li> Jump up ^ Flank, Lenny (May 24, 2016). "A History of European Armor". Hidden History . </Li>

Who developed many of the tools that facilitated the medieval agricultural revolution