CLIFFORD J. ROGERS is a Professor of History at the United States Military Academy and founding director of the West Point Digital History Centre. His many books and articles on medieval warfare have been recognized with awards from the Royal Historical Society's Alexander Prize to the Society for Military History's Distinguished Book Award and Moncado Prize, as well as two Verbruggen Prizes and the Bachrach Medal from De Re Militari. His recent work has focused on early gunpowder and gunpowder artillery. CLIFFORD J. ROGERS is a Professor of History at the United States Military Academy and founding director of the West Point Digital History Centre. His many books and articles on medieval warfare have been recognized with awards from the Royal Historical Society's Alexander Prize to the Society for Military History's Distinguished Book Award and Moncado Prize, as well as two Verbruggen Prizes and the Bachrach Medal from De Re Militari. His recent work has focused on early gunpowder and gunpowder artillery. David S. Bachrach is a professor of medieval history at the University of New Hampshire. His research interests include the administrative and military history of the Carolingian Empire as well as the medieval German and English kingdoms. PIERRE COURROUX is a former Newton International Fellow of the British Academy and a senior lecturer at the University of Pau.