In Islam, slave soldiers were often trained from youth to be loyal only to their owners. These slave armies often established dynasties of their own (see Mamluks; Janissaries). In medieval Japan and Europe, samurai and knights, respectively, owed military service to a lord. The European system depended on the feudal levy, which required knights and yeomanry to provide a fixed number of days of military service per year to a great lord. Because of this limitation on service and the poorly trained force that it produced, sustained military operations were difficult. Feudal armies were undermined by the development in England of the longbow, but they were destroyed by the introduction of gunpowder. Armed knights became easy victims of hand-carried firearms and castle walls could now be breasted by cannon.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.