1. Historical context

In 634 the Arabs invaded the Byzantine provinces of Palestine and Syria. By 645 they had already conquered them along with Egypt and Mesopotamia. Since 640 they had started raiding the interior of Asia Minor.

The reasons why the Arabs raided the Byzantine lands of Asia Minor almost annually were, apart from plundering and looting, mainly ideological and strategic. The war against the infidels was a religious duty for the Muslims, and at the same time could be exploited by Arab leaders to raise their status among the Arab population. Moreover, the continuous raids and pillage weakened the Byzantines and offered security to the Arab border regions.¹

Until the beginning of the 8^th century these raids were organized by caliphs who aimed to weaken the opponent and capture cities and islands in order to use them as military bases for the capture of Constantinople and the Byzantine Empire in general. When the attempts of the Arabs to capture Constantinople failed and especially after the middle of the 9^th century, the raids continued and became a provincial phenomenon along the stabilized eastern border, starting from Cilicia and the mountain range of Taurus, moving to Antitaurus, the west bank of Euphrates and the mountains of Pontos, before finally ending in the Black Sea.²

According to the Arab sources, the year was divided into three periods of raids. The winter period provided the opportunity for occasional raids only and lasted from the end of February until the beginning of March. The spring period started on 10 May and continued until 10 June. During the summer period (10 July – 8 September), raids of a bigger scale were organized.³ The mountainous terrain of the eastern border forced the invaders to use a small number of mountainous passes (kleisoures or clausurae, as the Byzantines named them – they were later organized into autonomous military units), most important of which were the Cilician Gates, the Adata passage and the Melitene passage.⁴

2. War tactics

2.1. First phase: defence

The continuous raids of the Arabs in the Byzantine lands since the 7^th century had forged a grid of military organization and tactics designed to repel the invaders, especially those of smaller scale raids. These were more harmful at a regional level than the bigger scale raids, since they were more sudden and caught the Byzantines by surprise.

The defensive zone of the Byzantines started from the border, where some kleisoures had already been organized into military units since the 7^th century. The duty of a kleisourarches or a tourmarches was to guard the border and inform his superiors should a raid occurred. Mounted patrols, guards and kaminoviglion were placed in neighbouring heights in order to relay information to the strategos of the theme.⁵

The duty of a strategos, apart from the gathering of his troops in order to repel the invaders, was to defend the civilian population. Special officials called expelatores were sent to every inhabited region and coordinated the evacuation of the civilian population to fortified cities or mountains. By the 10^th century a network of forts and fortresses had also been organized in order to defend the civilian population.⁶

2.2. Second phase: attack

Apart from evacuating the civilian population to safe locations, the tourmarches of a region followed the invaders upon their heels awaiting reinforcements from the strategos. If he outnumbered them, he attempted to intercept their maneuvers and localize the breadth of their pillage with his cavalry. Otherwise, the Byzantine tactics consisted in the use of infantry and ambush. The Byzantines avoided deploying their forces for a battle and preferred to ambush and annihilate the invaders in mountainous passes.⁷ The Byzantine handbooks of war advised the strategoi not to confront the Arabs as soon as they invaded, but to occupy the border kleisoures and wait for the invaders to return. The effectiveness of this tactic was due to the fact that the Arabs had lost a number of their forces during the long campaign, as well as their mobility because of the loot and the prisoners they carried along. That way the Byzantines ambushed and defeated in 950, 958 and 960 (in the Andrassos kleisoura) the Arab leader Sayf ad-Dawlah, returning to Syria after successful raids in Asia Minor. This tactic, however, got the civilian population in a predicament, since the army left them undefended against the enemy raids on purpose.

The Arab raids in Asia Minor ended in the decade of the 960s, when the Byzantines under Nikephoros Phokas captured Cilicia and a part of Syria, depriving the Arabs of their military bases. What played the most important part in the Byzantine counterattack was the fact that they had successfully changed the military balance after repelling the Arab raids for three centuries.

3. Consequences

The continuous conflicts on the Arab-Byzantine border affected the military organization of the Byzantine Empire. The nature of these conflicts forced Byzantium to distribute its forces throughout all its dominion, introducing the institution of themes. Moreover, the need for larger cavalry forces in order to repel the mobile invaders increased its importance and decreased the importance of infantry. At the same time, the continuous maneuvers decreased the ability of the Byzantine army to deploy its forces.⁸

The consequences on the economy of Asia Minor were more important. Due to the continuous pillage and destruction, as well as the insecurity among the local population, the levels of agricultural production and cattle-raising in Asia Minor fell. The conflicts disrupted transit trade as well and limited it to a regional level. The movements of friendly or enemy military forces, as well as the ever-increasing tax demands of the state in order to repel the invaders, also evoked great damage to the local economies of Asia Minor.⁹

The consequences on the demography of Asia Minor were similarly important. Asia Minor changed radically from the 7^th until the 10^th century. The population of the regions which were not threatened by the raids, such as the Pontos and Ionia, increased greatly.¹⁰ The population of the rest of Asia Minor, even though they did not abandon their homes massively, decreased. In order to face this problem, some emperors ordered the settlement of new populations in the Byzantine lands, mainly Armenians, and the removal of hostile populations from the border to other parts of the Empire.¹¹ These measures resulted in a change in the demography of the region. The most obvious change occurred in the cities. Some weakened and others disappeared completely. Most of them survived as administrative centres of limited jurisdiction. The demographic damage to the country and the weakening of the cities were the most important consequences of the Arab-Byzantine conflicts on Asia Minor.¹²