Military Forces

Two major works on tactics come from the late Roman period: Taktike Theoria by Aelianus Tacticus and De Re Militari ("On military matters") by Vegetius. Taktike Theoria examined Greek military tactics, and was most influential in the Byzantine world and during the Golden Age of Islam.
De Re Militari formed the basis of European military tactics until the late 17th century. Perhaps its most enduring maxim is Igitur qui desiderat pacem, praeparet bellum (let he who desires peace prepare for war).
Due to the changing nature of combat with the introduction of artillery in the European Middle Ages, and infantry firearms in the Renaissance, attempts were made to define and identify those strategies, grand tactics and tactics that would produce a victory more often than that achieved by the Romans in praying to the gods before the battle.
Later this became known as Military Science, and later still would adopt the scientific method approach to the conduct of military operations under the influence of the Industrial Revolution thinking. In his seminal book On War the Prussian Major-General and leading expert on modern military strategy Carl von Clausewitz defined military strategy as "the employment of battles to gain the end of war." According to Clausewitz