Chapter 4 - A Transition of War
The centuries of invasion, civil war, and general decay took their fatal toll on the Roman empire of the West. From the 4th century onward the legacy of Rome was gradually transferred to its eastern capital, Constantinople, where Roman emperors attempted to stem the tide of barbarism and preserve the essence of Roman culture. By 650 A.D. the empire of the east was resigned to the loss of the western provinces, and found itself confronted with numerous military threats, especially from Islam, closer to home. These threats occupied the empire's attention for the next 800 years, and it is a testimony to Byzantine greatness and skill that the empire survived and prospered for more than a millennium after the collapse of Rome until suffering its final defeat at the hand of Ottoman armies in 1453. The Western Roman empire had lasted for 500 years. The Eastern empire (395-1453) endured for over a thousand.
The imposition of Roman administrative machinery upon the Byzantine population in the early years kept the traditions of Roman military science and law intact, and preserved Roman culture and achievement for more than a thousand years until, as Allbutt noted, "Western Europe was once again fit to take care of them." Byzantium suffered no period of general degradation and decay like the Middle Ages in Europe and, for the most part, remained the most refined and developed culture in the world until the very end.
Vital to Byzantine survival was the maintenance of its military capability which, as Oman notes, "was, in its day, the most efficient military body in the world." Despite many evolutionary changes in details, the Byzantine military machine remained Roman in both its organization and values, and it continued to produce excellent soldiers and commanders long after the Roman legions had disappeared in the West. The basic administrative and tactical unit of the Byzantine army, for both cavalry and infantry, was the numerus comprised of 300-400 men, the equivalent of the old Roman cohort. Each numerus was commanded by the equivalent of a colonel. A division or turma was comprised of five to eight battalions commanded by a general. Two or three turmae could be combined into a corps commanded by a senior general called a strategos. The empire was geographically organized into provinces or themes, each of which had a military commander responsible for security with deliberately unclear lines between civil and military administration so as to give priority to military defense. For more than four centuries the Byzantine army numbered approximately 150,000 men almost evenly split between infantry and heavy cavalry forces.
Military manpower was obtained through universal conscription, but in practice recruiting and stationing military forces within each theme allowed commanders to recruit the best manpower from within each province. The army attracted the best families for its soldiers, thereby avoiding the fatal mistake of the Western empire which relied heavily upon barbarian soldiers while the best Roman citizens served not at all. Whereas Rome had relied heavily upon infantry until too late, the Byzantines adjusted to the new forms of highly mobile mounted warfare by relying primarily upon an excellent heavy cavalry of their own. Byzantine military commanders were quick to adopt a number of weapons and tactics of their enemies, so that as the infantry legion had symbolized the might of Rome, the mounted heavily armored horseman, the cataphracti, came to symbolize the military might of Byzantium.
The organizational infrastructure of the army of Byzantium was every bit as well-organized and efficient as it had been under the old Roman legions. The army had organic supply and logistics trains comprised of carts and pack animals to speed mobility, excellent siegecraft capabilities to include the full range of Roman artillery and siegecraft specialists, a fully articulated staff organization professionally trained in military academies, and a powerful navy to support ground operations. The genius of the Romans for military organization was preserved intact in almost all its earlier aspects.