On 1 January 1068, at the invitation of the widowed Empress Eudocia Makrembolitissa, Romanos IV Diogenes (1068Ė71) was crowned emperor (see above, p. 608). Two months later he set out for Membij in Syria, which he captured. Romanosí next campaign took place between spring 1069 and the winter of 1069/70. Although he drove the enemy from Larissa in Cappadocia, he did not manage to prevent the Turks from plundering Ikonion (Konya). The main battle, however, took place in 1071. In the spring of 1070 the emperor sent the kouropalat¯es Manuel Komnenos, nephew of the late emperor Isaac I Komnenos (1057Ė59), as strat¯egos autokrat¯or of the Byzantine eastern army.Manuel had to defend the theme of Chaldia, which was being threatened by a certain Arisghi, brother-in-law of Sultan Alp Arslan. An important battle took place at Sebasteia in the autumn of 1070. The Byzantines were defeated; but then Manuel Komnenos persuaded Arisghi, who was at odds with the sultan, to join the emperorís side. Meanwhile in AugustĖSeptember, Alp Arslan took Arjish (Archesh) and Manzikert, moving on to Mayyafariqin, Amida and then Edessa, which he besieged but did not manage to take. By April 1071 Alp Arslan was besieging Aleppo. His primary aim, however, was to campaign against the Fatimid forces in Syria. At this juncture a Byzantine embassy arrived, offering Membij in exchange for Arjish and Manzikert. The sultan, who needed to secure his northern flank, agreed to a peace treaty on condition that the emperor paid a yearly tribute. But in the meantime Afshin al-Turki had penetrated deep into the territory of Byzantine AsiaMinor (see above, p. 701) taking Chonai and ravaging the environs ofTzamandos. It was at this moment when news of Afshinís audacious raid arrived in Constantinople that Romanos IV decided to declare open war. In July 1071, the Byzantine army moved across the River Sangarios to Caesarea and the emperor arrived at Theodosioupolis; at this point the sultan was in Vostan, near Narek. By mid-August Romanos had retaken Manzikert. Alp Arslan believed that Diogenes had broken the truce; he abandoned plans to go to Syria and hastened back towards the Byzantine army. However, he offered to sign a peace treaty with Romanos once again. The emperor refused. The battle ended in humiliating defeat for the Byzantines, with Romanos IV being captured and brought before Alp Arslan on 26 August 1071. The causes of the Byzantine defeat were manifold and complex. The first was Romanosí misjudgement of Alp Arslanís strategy. Had Romanos known that the sultan intended to concentrate on Syria instead of attacking the Byzantine borders, and that he faced serious financial difficulties in paying his own soldiers, the battle could have been averted. Secondly, the Turks employed superior tactics; they were mostly horsemen armed with bows and arrows, capable of striking the enemy while themselves staying out of range, thus rendering the Byzantine armyís close formations a disadvantage. Not only did Byzantine tactics fail against the Turks; the action of the imperial army depended far too much on the instructions of its commander-in-chief. Romanos realised too late that the sultan was approaching, and divided his forces by sending large contingents in the direction of Akhlat. Finally, the emperor was betrayed by the proedros Andronikos Doukas, whose detachment withdrew when the outcome of the battle was still uncertain (see above, p. 608). Given the crushing nature of the defeat, the terms of the peace treaty were comparatively moderate. Reparations came to a total of one and a half million dinars: an immediate payment of 300,000 dinars, with the balance to be paid as an annual tribute of 60,000 dinars, implying that the peace treaty was expected to last for twenty years.11 Romanos was also required to cede four cities in northern Syria and Armenia to Alp Arslan Ė Edessa, Membij, Antioch andManzikert Ė before the sultan would release him. Alp Arslanís intentions remained the same as they had been before the battle: he wanted the empire to be his peaceful neighbour and to keep his flanks in Syria secure for his further advance against the Fatimid caliph in Egypt. Although in the event the Byzantines only ceded Manzikert, these four cities were the key Byzantine strongholds in northern Syria and Armenia. And although the peace treaty in theory gave the empire a twenty-year respite from attacks by the sultanís army, it could not stop the incursions of the other Turks. The bitter experience of the three decades before the battle of Manzikert had shown that the Byzantinesí defence of the region relied on a strong field army, working in liaison with the large fortressesí garrisons. After 1071 the main field army was no longer an operational military unit, although the empire still possessed battle-worthy detachments.12 Had there been a strong government, the army could still have been restored to a level comparable with the enemyís. Instead, the empire plunged into civil war.