The development of artillery in the 15th cent. greatly diminished the value of medieval castles. One of the great military problems of the Renaissance and the succeeding centuries was to develop fortifications able to withstand artillery. Moats were deepened to afford greater protection and widened to put artillery at a greater distance. Walls were lowered, thickened, slanted, and rounded to resist projectiles and make them ricochet, and stone bulwarks were thrown up in front of towers and gates. New fortifications, set in ditches, were buttressed to withstand heavy shot, and defensive guns were mounted behind earthen ramparts. In fortifications of towers (roundels) connected by walls (curtains), there were areas that could not be covered by defensive fire from the towers. Hence artillery positions, or bastions, were constructed at angles to the main wall. The proper distribution of bastions became the main preoccupation of military engineers.
The science of military engineering reached a high point in the wars of Louis XIV. Sébastien le Prestre, marquis de Vauban, who worked out fortification and siege methods in the late 17th cent., has perhaps the most illustrious name in the history of fortification. His methods, supported by the work of others such as Menno van Coehoorn, were used for centuries.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.