Strategy is the means by which a commander may defend his own lands and defeat his enemies. The general is the one who practices strategy. 1
At the end of the sixth century, and following Justinian’s reconquests in Italy and North Africa, East Roman forces were disposed in seven field armies and a large number of smaller regional divisions along and behind the frontier regions of the empire. 2 The former were known as comitatenses, were each commanded by a magister militum, “Master of the Soldiers”, and were organized into divisions for the East, Armenia Thrace, Illyricum, Africa, and Italy, with two further “praesental” divisions (i.e. they were “in the presence” of the emperor) based in northwest Asia Minor and in Thrace to defend Constantinople. The troops making up the frontier divisions and permanent garrisons were known as limitanei, mostly composed of older legionary units, together with their attached auxiliaries, augmented by auxiliary and legionary cavalry forces brigaded together to provide local static and mobile reserves. 3 By the end of Justinian’s reign there were over 25 such commands based in both the frontier provinces of the empire and inland, from Scythia in the northwest Balkans through the Middle East and Egypt to Mauretania in northwest Africa. 4 Although the titles of units often reflected the category to which they were originally allocated, cross-postings between divisions complicated matters considerably, and the practical differences in military terms between field troops and limitanei were not always very clear. Civil and military authority had been combined in several regions, the better to deal with internal security matters: in Egypt, for example, where the post of dux of the Thebaid was given civil authority, and the position of praefectus Augustalis (civil governor) was combined with that of the military commander, the dux Aegypti; or in southern Asia Minor, where civil and military authority was combined in Pisidia, Lycaonia and Isauria.