Historians writing during the later nineteenth and the twentieth centuries unambiguously recognized the importance, indeed the central role, played by siege warfare in European military history during the Middle Ages, i.e., from the dissolution of the Roman empire in the West at least until the emergence of high quality gunpowder weapons. Thus, for example, Hans Delbruck observed: "Throughout the entire Middle Ages we find…the exploitation of the defensive in fortified places."(1) Charles Oman, Delbruck's contemporary, took much the same position. (2) Recognition of the importance of siege warfare, however, did not lead historians to the obvious conclusion that the subject merited intensive study as an essential aspect, if not the essential aspect, of medieval military history, and as a key to our understanding of the Middle Ages. Indeed, Henry Guerlac observed in 1943: "nothing is more conspicuously lacking in the field of military studies than a well-illustrated history of the arts of fortification and siegecraft."(3) Yet, only two years later Ferdinand Lot wrote in the introduction to his classic study, L'Art militaire et les armees au moyen age et dans le proche orient: "il laisse de cote une parti essentielle du sujet, la Guerre de sieges, qui a joue un si grand role dans les siecles qu'on a passes en revue."(4) In 1980, Philippe Contamine noted: "In its most usual form medieval warfare was made up of a succession of sieges accompanied by skirmishes and devastation." Indeed, Contamine goes so far as to suggest that medieval warfare was dominated by "fear of the pitched battle" and a "siege mentality." Like Lot, Contamine did not provide a major change of focus.(5) The failure of military historians to pursue the study of medieval siege warfare can be rather simply, if not simplistically, explained as a result of "presentism." During the later nineteenth century and throughout much of the twentieth, military planners cleaved to the doctrine which is often styled "the strategy of overthrow." This emphasized "the importance of battle to such a degree that they regarded it as the only important act in war."(6) Indeed, those historians who wrote medieval military history, whether professional scholars or amateurs, not only would appear to have adhered to this doctrine but regarded any other way of conducting warfare as ostensibly unworthy of study.(7) Thus, when scholars such as Delbruck, Oman, and Lot wrote medieval military history they looked for battles to study. Even more importantly, they focused attention upon the so-called "knights" or "heavily armed cavalry." This element in society putatively dominated the battlefield, and thus they are also thought to have dominated medieval warfare with the shock of their mounted charge. This model is still regarded as the "key" to understanding the military history of the Middle Ages.(8)