The Expansion of Islam in the Mediterranean Area (7th-9th Centuries)

Within ten years of Mohammad's death in 632 the armies of Islam stormed out of Arabia, overwhelmed the Sassanians of Persia, and wrested Syria, Palestine and Egypt from the Byzantine Empire. The Arabs were formidable because of their mobility. In 636 they concentrated at Yarmuk beyond the Jordan and completely defeated the Byzantine armies. The victory brought them Damascus, which became their headquarters. In 637/8 Jerusalem fell, followed quickly by Antioch and Edessa. The conquest of Palestine and Syria was completed in 642 when Caesarea was captured. Gaza had already fallen, and the conquest of Egypt was completed with the surrender of Alexandria (642).

The Byzantine Empire had to meet the challenge. It contained the Arabs in Anatolia by evolving the theme system of defence. Initially, this meant dividing Anatolia into three military commands: Opsikion, Anatolikon and Armeniakon. The Opsikion, originally the strategic reserve, was now

Quartered across the approaches to Constantinople. The Anatolikon was the old army of the East, but now withdrawn to defend south-eastern Anatolia. The Armeniakon was the army of Armenia, now established in northern Anatolia and covering the routes from Melitene and the middle Euphrates.

The threat from the Arabs was all the more formidable because they took to the sea. They occupied Cyprus (649-50) and destroyed the Byzantine fleet at Phoinix (655) off the coast of Anatolia. Constantinople was blockaded from 674 to 678, but this attack was beaten off with Greek fire. Another assault similarly failed in 718. From then on Constantinople and Anatolia were relatively secure, though there were intermittent raids down to the mid-ninth century, some penetrating to within striking distance of Constantinople.

The Byzantines were less successful in holding the Arabs in the Mediterranean. Carthage finally succumbed in 697, and from their new capital of Kairuan the Arabs converted the Berbers. This fuelled the Muslim advance into Spain. Toledo, the Visigothic capital, fell in 711 and by 718 the conquest of Spain was virtually complete. The Muslims advanced northwards across the Pyrenees, but their defeat in 732 by the Franks at the battle of Tours limited any further conquests in this area. Their efforts were concentrated in the Mediterranean. Crete fell in 824 and a start was made on the conquest of Sicily from the Byzantines. They established a base at Palermo, but it was not until 878 that the Byzantine provincial capital of Syracuse fell. In 840 Bari was captured and became the centre of an emirate which terrorized southern Italy and the Adriatic. It was recovered in 876 by the Byzantines and a degree of stability was restored in the central Mediterranean.

The Muslim advance stretched Byzantine resources to their limit, for it was also involved in the Balkans. In 582 Sirmium fell to the Avars, and their Slav tributaries swarmed into the Balkans. They settled on a permanent basis and penetrated as far south as the Peloponnese, where Monemvasia provided a refuge for the native population. In 679 the Bulgarians crossed the Danube and settled the lands to the south. Byzantine territories were now limited to Thrace and a few towns along the fringes of the Aegean, such as Thessalonica, which withstood a series of Slav sieges. To hold these areas the themes of Thrace and Hellas were established at the end of the seventh century. From the late eighth century a determined effort was made to strengthen the Byzantine hold in Europe. This culminated in the reoccupation of the Peloponnese and the creation (c. 805) of the theme of the Peloponnese with its headquarters at Corinth.

The Byzantine Empire survived the assaults and losses of territory which occurred from the seventh to the early ninth centuries. In many ways, it emerged all the stronger, thanks to its capital Constantinople and the evolution of the theme system.

M. Angold