The geographical situation of the empire offered, in this respect, both disadvantages and advantages. In the former case, the fact that potentially hostile powers were to be found on at least two, and usually three, fronts (Balkan, Syrian/Anatolian and maritime) meant that resources were always spread very thinly. In the latter, the mountain ranges which protected the Anatolian territories of the empire, together with the associated climatic conditions, appear to have discouraged attempts from the Arab Islamic powers to the south to occupy the areas beyond the Taurus-Anti-Taurus frontier zone, except very occasionally and, ultimately, unsuccessfully. And even when fortresses on the Byzantine side of this zone were seized and occupied, the Byzantine riposte was usually rapid and effective, inhibiting any longer-term build-up of military strength on the part of the invaders. In the Balkans, the situation was by no means so clear cut, but on the other hand neither the empire nor its closest powerful neighbour, the Bulgar state, enjoyed a natural boundary (until the empire extinguished Bulgar independence and recovered control of the regions up to the Danube in the late tenth century), and the political imbalance between the two was never as marked as between the Umayyad and Abbasid caliphates at the height of their power (c. AD 660–740 and 780–840) and the empire.
This difficult strategic situation encouraged an extremely close involvement with the demands of international diplomacy, of course, without which the empire would quickly have foundered. In turn, this stimulated the consolidation fairly early on of a relatively consistent, albeit conjuncture-bound, general strategy for the empire. Naturally, this was not written down, nor was it necessarily constantly present in the thoughts of the empire’s political leaders and their advisers. But it possessed a certain momentum and direction of its own. Complex institutional arrangements, particularly those with which we are concerned here, evolve certain well-worn methods for achieving certain ends, and it is usually only in times of major crisis and organizational upheaval that such methods can be substantially altered. This is what happened during the seventh century, of course, and again, although on a more gradual scale, from the middle of the eleventh and into the early twelfth centuries. The ramified relationships between armed forces and their requirements, the resources available in different regions of the empire at any given time, as well as important features of the practice of diplomacy (such as time required for the diffusion and transmission of information, for example, or in respect of the movement of soldiers and materiel), as well as the psychology of the situation, these are all factors which played a role, and of which the government at Constantinople had to be aware in order to make any meaningful calculations of its own when confronted by a threat. Such factors in turn imposed their own demands—in time, in resources, in the pace of recruitment and dispositions of troops, and so forth—upon the state, operating in effect according to their own, institutionally determined agenda. Thus, while the administration and rulers at Constantinople acted according to their own, context-bound understanding of the political and strategic needs of the moment, they also worked within a framework which imposed itself upon them in respect of how policy and strategy were realized in practice.