Kilij Arslan II and The Seljuk Turks
For more details on this topic, see Battle of Myriokephalon.Between 1158–1161, a series of Byzantine campaigns against the Seljuk Turks of the Sultanate of Rûm resulted in a treaty favourable to the Empire. According to the agreement certain frontier regions, including the city of Sivas, should be handed over to Manuel in return for some quantity of cash. However, when it became clear that the Seljuks had no intention of honouring their side of the bargain, Manuel decided that it was time to deal with the Turks once and for all. Therefore, he assembled the full imperial army, and marched against the Seljuk capital, Iconium (Konya). Manuel's strategy was to prepare the advanced bases of Dorylaeum and Sublaeum, and then to use them as to strike as quickly as possible at Iconium.
Yet Manuel's army of 35,000 men was large and unwieldy – according to a letter which Manuel sent to King Henry II of England, the advancing column was ten miles (16 km) long. Manuel marched against Iconium via Laodicea, Chonae, Lampe, Celaenae, Choma and Antioch. Just outside the entrance to the pass at Myriokephalon, Manuel was met by Turkish ambassadors, who offered peace on generous terms. Most of Manuel's generals and experienced courtiers urged him to accept the offer. However, the younger and more aggressive members of the court urged Manuel to attack; he took their advice and continued his advance.
Manuel made serious tactical errors, such as failing to properly scout out the route ahead. These failings caused him to lead his forces straight into a classic ambush. On 17 September 1176 Manuel was decisively defeated by Kilij Arslan II at the Battle of Myriokephalon (in highlands near the Tzibritze pass), in which his army was ambushed while marching through the narrow mountain pass. The Byzantines were too dispersed, and were surrounded. The army's siege equipment was quickly destroyed, and Manuel was forced to withdraw – without siege engines, the conquest of Iconium was impossible. According to Byzantine sources, Manuel lost his nerve both during and after the battle, fluctuating between extremes of self-delusion and self-abasement; according to William of Tyre, he was never the same again.
The terms by which Seljuk Sultan Kilij Arslan II allowed Manuel and his army to leave were that he should remove his forts and armies on the frontier at Dorylaeum and Sublaeum. However since the Sultan had already failed to keep his side of the earlier treaty of 1162, Manuel only ordered the fortifications of Sublaeum to be dismantled, but not the fortifications of Dorylaeum. Nevertheless, defeat at Myriokephalon was an embarrassment for both Manuel personally and also for his empire. The Komnenian emperors had worked hard since the Battle of Manzikert, 105 years earlier, to restore the reputation of the empire. Yet because of his over-confidence, Manuel had demonstrated to the whole world that Byzantium still could not defeat the Seljuks, despite the advances made during the past century. In western opinion, Myriokephalon cut Manuel down to a humbler size: not that of Emperor of the Romans but that of King of the Greeks.
The defeat at Myriokephalon has often been depicted as a catastrophe in which the entire Byzantine army was destroyed. Manuel himself compared the defeat to Manzikert; it seemed to him that the Byzantine defeat at Myriokephalon complemented the destruction at Manzikert. In reality, although a defeat, it was not too costly, and did not significantly ruin the Byzantine army. Most of the casualties were borne by the right wing, largely composed of allied troops commanded by Baldwin of Antioch, and also the baggage train, which was the main target of the Turkish ambush. The limited losses inflicted on native Byzantine troops were quickly made good and in the following year Manuel's forces defeated a force of "picked Turks". John Komnenos Vatatzes, who was sent by the Emperor to repel the Turkish invasion, not only brought troops from the capital but also was able to gather an army along the way which allowed him to score a victory over the Turks at the Battle of Hyelion and Leimocheir; a sign that the Byzantine army remained strong and that the defensive program of western Asia Minor was still successful. After the victory on the Meander, Manuel himself advanced with a small army to drive the Turks from Panasium, south of Cotyaeum. However, in 1178 a Byzantine army retreated after encountering a Turkish force at Charax, allowing the Turks to capture many livestock. The city of Claudiopolis in Bithynia was besieged by the Turks in 1179, forcing Manuel to lead a small cavalry force to save the city and then, even as late as 1180, the Byzantines succeeded in scoring a victory over the Turks.
However, the continuous warfare did have a serious effect upon Manuel's vitality; he declined in health and in 1180 succumbed to a slow fever. Furthermore, like Manzikert, the balance between the two powers began to gradually shift – Manuel never again attacked the Turks and, after his death, they began to move further and further west, deeper into Byzantine territory.
Read more about this topic: Manuel I Komnenos