The institutions comprising the army, tax-collection and other administrative apparatus and the law are more familiar. Some deliberately evoked ancient Rome, and inscriptions on coins – themselves a clear symbol of continuity – styled rulers ‘emperors of the Romans’ from around 812 onwards (see below, fig. 28 on p. 418). The organisation and role of the Byzantine navy have been set out in authoritative works.34 But the army has received the lion’s share of scholarly attention, in part reflecting the coverage of military matters in Byzantine literary sources. Military history features in many of our chapters, and the tactical manuals available in translation are noted below (see below, pp. 87–9). The formal units, prescribed methods of fighting and even some pay rates are known from snapshots in particular sources, and certain developments, the metamorphoses of the seventh and eighth centuries and the revival of large-scale offensive warfare in the tenth, are beyond reasonable doubt.35 Likewise with the retrenchment carried out by Alexios I (1081–1118); the capability of Manuel I Komnenos’ (1143–80) forces; and the robustness of the armed forces in LascaridNicaea and during Michael VIII’s Constantinopolitan regime.36 Nonetheless, major questions about the army remain unresolved and sometimes contentious. Aspects of the arrangements for maintaining a pool of operational and potential military manpower in the provinces are opaque, probably because of their flexibility and the late date when they were formally codified. But it is clear that for a full-time core force, iconoclast emperors and their successors relied on ‘Byzantine praetorians’, elite units generally stationed in or near the capital; and to be enrolled in the military registers in the provinces brought remuneration and status as well as potentially heavy obligations.37 More controversial is the question of the armed forces’ size in the medieval period. The figures provided by contemporary Arabic writers and occasional Byzantine references would suggest operational field armies of 80,000 or more. But such figures jar with Byzantine chronicles’ assumptions about the difficulty of campaigning on more than one front at a time, and an abiding imperial concern was to impress upon outsiders that Byzantine armies were larger than in fact they were.38 The discrepancies in figures probably reflect not only imperial disinformation, but also actual fluctuations of various kinds – in the empire’s population size; in the number of units of outsiders employed for short-term campaigning; and in the authorities’ resort to ad hoc call-ups of all remotely serviceable males. Such call-ups might be made in dire emergencies, or even for occasional offensives. 39 Arms-bearers originating from societies attuned to violence played an important part in maintaining the empire’s security from Justinian’s era onwards, the Armenians being pre-eminent.40 They seldom receive extensive attention in Byzantine narratives; even the 6,000 or so Rus warriors sent to the aid of Basil II c. 988 are known to us mainly from non-Byzantine sources (see below, p. 525). This was an era of imperial expansionism, but in earlier periods, too, externally based warriors were employed for specific operations, temporarily swelling the ranks of imperial forces. The question of the figures for the Byzantine armed forces bears heavily on the history of the empire’s administration. The forces were the largest item of expenditure, providing much of the raison d’ˆetre for the apparatus for raising revenue and spending it. If, as seems likely, the empire could get by with modest-sized, highly disciplined armed units for much of the time, counting on a modicum of cooperativeness from eligible military manpower, suppliers and carriers in those places under threat, financial outlay was correspondingly limited. This combination of cost-effectiveness and reliance on cooperative locals lessened the need for a sizable administrative apparatus. Direct supervision from the capital could be focused on the districts that were more fiscally lucrative or the most strategically important, a form of ‘hot-spots’ and ‘cold-spots’ or inner and outer zones of governance discernible in varying permutations and regions throughout Byzantium’s history (see below, pp. 498–501, 653–4, 664–5, 668, 827–8). The outlines of central administration from the late seventh and eighth centuries on are only dimly discernible. They seem to comprise departments of senior officials dedicated to particular tasks such as revenue-raising or expenditure, but with overlapping functions and without a firmly cast hierarchy of great offices of state.41 Their activities could be readily scrutinised by the emperor and his closest associates and counsellors, a costeffective form of flexible ‘flat-management’ provided that the volume of business was fairly limited, the emperor or his closest associates reasonably assiduous. The names of the higher or more durable offices are known to us. But details come mainly from the orders of precedence of title- and office-holders at palace receptions, and we lack texts clearly setting out functions and lines of accountability in full.42 This deficiency is partly made up for by the survival of many lead seals belonging to senior officeholders. A major step towards matching such seals with what else is known of the central administration was made by Vitalien Laurent, followed up by other sigillographers, and the series Studies in Byzantine sigillography, notably volumes 7 and 8, offers useful additions and updates.Work on the prosopography of the middle Byzantine period is collating seals with what the written sources relate about individuals’ career patterns. This can yield statistical data as well as case studies of individuals working in the administration, and the online database is designed to offer means of access to non-specialists.43 The forementioned orders of precedence also list the strat¯egoi and other senior officials serving in the provinces but expected to attend court functions quite regularly. Collation of these with Byzantine narratives and Arabic sources yields a rough picture by the ninth century. The strat¯egoi were military commanders at the head of armed units. Their judicial, levying and requisitioning powers were sweeping but did not permanently supplant other, more painstaking forms of tax-collection: this was primarily the task of officials answerable to the administration in Constantinople.44 The scope of the strat¯egoi within their respective themes is not wholly clear, and the territorial extent of the themes is seldom delineated precisely, perhaps because they were slow to assume fixed, territorial form. One clear development is the creation of smaller command units, known as kleisourai (literally, ‘passes’), to firm up defences in the Taurus mountain regions.45 Towns and other fortified population centres were fixed points in later seventh- and eighth-century administration, being also the likely sites of apoth¯ekai, state depots for storing revenue proceeds such as grain, and for issuing supplies and probably also equipment to soldiers.46 But the dealings, formal and informal, of state agencies with outlying countrydwellers emerge fromour sources only fitfully. The authorities could seldom guarantee full protection to those far removed from strongholds or fortified refuges.