The emperors in the eighth century confronted an empire that had been ruralised and depopulated, and teetered on the brink of ruin. The situation was particularly dire when Leo III took power in 717, as Constantinople was besieged by land and sea by enormous Arab forces. Leo followed a succession of emperors – six in the twenty-two years following the first deposition of Justinian II in 695 – which marked a crisis for the empire.64 The failure of the siege in 717 had considerable repercussions; this was the first major setback in the Arab conquest which had begun in the 630s and had continued unrelentingly ever since (see below, pp. 370–7; above, p. 221). However, it did not guarantee the security of an empire still very much under threat. It was because of this threat that the Isaurian emperors and their successors, with the exception of Irene, introduced reforms designed to strengthen the empire against its enemies. It is often difficult to unscramble the Isaurians’ reforms from the attempts of Heraclius and his successors to cope with the Arab invasions and the loss of the eastern provinces; only in the ninth century do we become better informed about the state of play. But there is now a tendency to reassess the role played by the Isaurians, long minimised because of their discredited religious policies. The threat which hung over the empire explains why absolute priority was given to the army. Organising the army and maintaining it well required that the state apparatus be placed under direct authority of the emperor; victory depended on the purity of faith of the Christian people. The empire’s defences were fragmented into small units stationed in fortresses, so that walls became as important as men (see above, fig. 2 on p. 57). Repair of the walls went on incessantly, the unrivalled champion in this being Michael III (842–67), at the very end of the period. In Constantinople after the earthquake of 740 Leo III paid for the restoration of the walls, previously the inhabitants’ responsibility, out of the imperial treasury, raising the City taxes by 813 per cent (a tax of one miliar¯esion per nomisma, called the dikeraton). Inscriptions on the land walls near the Sea ofMarmara record this work.65 Theophilos, for his part, repaired the walls near the Blachernae district and large sections of the sea walls.66 At Nicaea the walls were restored by Leo III and Michael III.67 Leo III (or Leo IV) sent a spatharios to repair the walls of Rodandos on the Arab border, and Leo IV sent the strat¯or Isaac, better known as Theophanes the Confessor, to repair those of Kyzikos.68 Following the pattern at Constantinople, these repairs were paid for by the local inhabitants, though carried out under the orders of an imperial official. The human element of the empire’s defence is more complicated than that of the physical walls, and many points remain unclear. At the beginning of the eighth century the army was based in the provinces and made up of different corps redeployed throughout Asia Minor after 636, following their withdrawal from the east. The troops of the magister militum per Orientem were stationed in central Asia Minor, their name Hellenised to Anatolikoi (from the Latin Orientales) and magister militum being translated to strat¯egos. The troops of the magister militum per Armeniam were deployed in northern AsiaMinor and took the Greek name of Armeniakoi; those of the magister militum per Thracias, which had been sent as reinforcements to the east, were pulled back to the west coast of Asia Minor and took the name of Thrakesioi. Finally, that part of Asia Minor closest to Constantinople had remained the quarters of the imperial guard, the Opsikion (see above, p. 240). These army units became known as themes (themata), a generic name whose etymology is disputed. By the beginning of the ninth century, theme had come to mean the territory on which a corps was stationed, with each unit’s strat¯egos based in the theme’s capital: Amorion in the Anatolikoi, Euchaita in the Armeniakoi, Chonai in the Thrakesioi and Nicaea in the Opsikion. Similarly, at the end of the seventh century new army corps were installed in Sicily, Hellas and Thrace, each commanded by a strat¯egos. This currently accepted model for the emergence of the themes has replaced that suggested by George Ostrogorsky.69 A further development saw the subdivision of the existing army corps, or themes, for tactical reasons; at the beginning of the ninth century the theme of Cappadocia was created in the Anatolikoi, with its capital at Koron; and in the Armeniakoi, the themes of Paphlagonia and Chaldia were established. But themes could also be subdivided for political reasons, as was the case with the Opsikion. All too often involved in plots, it was broken up into the Boukellarioi (768) and Optimatoi (c. 775) and these were simultaneously demoted from combat to rearguard units. The Opsikion theme proper retained only the western part of its former territory (Phrygia, the Hellespont and western Bithynia). Moreover, several new themes were created: in Crete, probably in the eighth century, and in Macedonia, the Peloponnese and Cephalonia in the ninth century. As regards the fleet, the Kibyrrhaiotai (from the city of Kibyrrha in Caria) had reinforced the Karabisianoi at the end of the seventh century and then replaced them to ensure protection of the southern coasts of Asia Minor, which were also guarded by the fleet of the Aegean Sea in the eighth century. 70 Access to the western Mediterranean was controlled by the fleet of the Helladikoi, which revolted in 727, and a fleet of Sicily also appeared in the 750s.71 In organisational terms, themes were subdivided into tourmai, droungoi and banda. The tourma, at the head of which was a turmarch, and the bandon, under the orders of a count (kom¯es), were assigned to a territory, whereas the droungos was a tactical unit, under the orders of a droungarios. 72 The numbers of men in a unit varied by region and over time, and figures suggested for individual themes are no more than rough estimates.73 According to Theophanes, Constantine V mobilised the entire Byzantine army against the Bulgars inOctober 773 (or 774); this totalled some 80,000 men, drawn both from the provincial – thematic – units and from the elite regiments stationed in the capital (tagmata). This figure is considered reasonable by some scholars, but far too high by others,74 and should be compared with information given at the end of the ninth century by Leo VI in his Tactica: according to Leo, the cavalry themes had 4,000 men each, 2,000 per tourma.75 From the mid-eighth century on, the tagmata stationed at Constantinople consisted of the Schools (scholai) and excubitors (exkoubitoi), old guard units which over the centuries had become largely ceremonial. Constantine V made them operational again and it was these tagmata who surrounded the emperor on the battlefield and whose arms were provided by the state.76 The tagmata – who prefigured the professional army of the tenth and eleventh centuries – were reinforced by Constantine V’s successors, though the Schools were demoted for a time under Irene, punishment for their fervent iconoclasm in hindering the meeting of the iconodule council in 786; they were replaced by another tagma, the Arithmos, formed out of banda from various themes.77 Unlike the troops of the tagmata who were full-time, those of the provinces were only mobilised for campaigns during the summer months and sometimes served outside their theme; natives of the AsiaMinor themes might even be employed in Europe.78However, some thematic soldierswere permanently on duty if they guarded a fortress, since fortresses had standing garrisons. The conditions under which soldiers were recruited is a question upon which much has been written; however, it remains an open question, involving as it does the entire system of taxation, an understanding of which, in turn, depends on one’s interpretation of the empire’s monetary circulation. There is agreement on some points: that thematic soldiers were based throughout the whole territory of a theme; that they were responsible for their own maintenance, since they had to present themselves for service with their equipment;79 and that the administration provided for their needs on campaign. Various suggestions have been put forward as to how soldiers paid for their equipment and how their service was remunerated. One is that the tenth-century system – that military service was inextricably linked with the holding of inalienable, exempted land – had, in fact, been in place since the seventh-century withdrawal of troops from the east: in effect, troops whom the state could no longer pay in cash were paid in land. Based on the numismatic records available before c. 198080 and on the disappearance of imperial estates between the sixth and tenth centuries,81 this interpretation is intellectually tempting and has been favoured by those who consider military service as a fiscal obligation, bound up with a plot of exempted land.82 However, as has often been noted,83 such an interpretation jars with the fact that those few contemporary sources which mention soldiers contain no evidence of compulsory military service in connection with land; these sources include the Ecloga, the Chronicles of Theophanes and Nikephoros, the Lives of Philaretos and Euthymios the Younger, and the letters of Theodore the Stoudite. Chapter Sixteen of the Ecloga, often cited but yet to be examined in detail, gives an idea of the position of soldiers under the Isaurians. When soldiers (strati¯otai) were enrolled (strateuomenoi), their name and place of origin were inscribed on the theme’s military roll, as well as on that of the central office of the strati¯otikon in Constantinople. Enrolment entailed military responsibilities: going to war, when called up, fully equipped with horse, harness and arms. It also entailed benefits: soldiers received a regular wage, which was paid whether or not they were on campaign, as well as extra wages during combat, booty, and bonuses from the emperor or strat¯egos. The regular wage (roga) was an annuity due to those who held the office of soldier, the so-called strateia. The household (oikos) in which an enrolled man lived, and which he could leave for another, was also probably exempt fromsupplementary taxes and impositions, although there is no mention of this in the Ecloga. Furthermore, the term strateia was not confined to soldiers. Under the Isaurians, every individual inscribed on the administrative roll by virtue of his office – in effect, everyone in imperial office, including ecclesiastical office – was deemed to hold a strateia, and thus entitled to receive a roga ‘from the hand of the emperor’, as well as rations in kind. Strateiai could either be bought or granted out by the emperor.84 The ways in which military strateiai changed hands are not altogether clear. Elderly soldiers might be taken off the rolls and thus forfeit their strateia; but on the other hand, soldiers’ widows had to furnish a fully equipped soldier – or the equivalent sum – if they wanted to keep the strateia, i.e. to continue receiving the roga and, perhaps, tax exemptions for the household. This latter practice was abolished under Irene, but it must subsequently have been re-established, as we find it in use around 840 in the Life of Euthymios the Younger.85 Irene’s measure forced her successor Nikephoros to make up for the soldiers who had thus been lost to the army, giving rise to the second in the list of this emperor’s ‘vexations’ decried by Theophanes. Nikephoros decreed that the poor from the villages should be enrolled as soldiers (strateuesthai); theywere to be equipped at the expense of their fellowvillagers who, in addition, were to pay 1812 nomismata for each poor man so enrolled. The latter sum has generally been understood to be the price paid for the equipment.86 But it could also be understood as the price of the soldier’s strateia. This would imply that the enrolled man’s roga was paid not directly to him – though he retained any extraordinary earnings – but to those who had jointly bought the strateia for him (the syndotai) and who, according to article 18 of the Farmer’s law, paid his taxes and had the use of his land.