E.W. Brooks & W.J. Corbett 
The Cambridge Medieval History – Book VIII [EPUB ebook] 
The Arab-Byzantine Wars and the Early Middle Ages

The Arabs first invaded Asia Minor during the commotions of 641. In 642 a plan of Valentine for a combined attack on them was frustrated by his defeat; but Theodore and Procopius penetrated as far as Batnae, and an Armenian force occupied Amida and nearly reached Edessa before they were routed. In 643, Valentine having returned to Constantinople, the enemy again entered Asia Minor, and Arabissus capitulated to Umair. In 644 Muawiya, amir of Syria, took and plundered Euchaita; and in 646 after besieging Caesarea for ten days he ravaged the neighbourhood, returned, and forced it to pay tribute, afterwards vainly attacking Amorium. On this expedition he found the Cilician fortresses deserted and left garrisons in them till his return, but in 647 had them destroyed. In 649 Habib, and in 651 Busr, raided Isauria, and in 651 Sufyan also invaded Roman territory from Germanicea, while in 649 Muawiya placed a fleet on the sea and plundered Constantia in Cyprus, but retreated on the approach of a Roman fleet under Cacorizus the chamberlain.
These were only plundering expeditions: but about 647 Habib occupied Melitene, Sozopetra, and Adata; and, as the war had gone against the Romans, Constans in 651 sent Procopius to treat for peace with Muawiya (the Caliph Othman was ignored), and a truce was made for two years, the Emperor paying tribute and leaving Gregory, the nephew of Heraclius, as a hostage.
The truce of 651 was hardly more than nominal; for the secession of Armenia led to the Emperor’s expedition to that country (652) and to the outbreak of fresh hostilities there, and after the expiration of the armistice the war was renewed on a larger scale than before. Great preparations were made by Mudawiya for an attack by sea and land upon Constantinople. He himself, starting from Melitene, took Ancyra and advanced to Dorylaeum (653), destroying all the fortresses on the way. Meanwhile ships were being hastily built at Alexandria, Tripolis, and other places; and in 654 a fleet under Abul-Awar after occupying Cyprus pillaged Cos, Crete, and Rhodes (where the famous colossus, long since fallen, was broken up and sold to a Jew). But, while the work was going on at Tripolis, two Roman brothers, Muawiya’s slaves, liberated the prisoners, and, with their help killed the governor and his guard, burnt the ships, and escaped by sea to Roman territory. Muawiya, who was probably recalled by the news of this disaster, did nothing this year beyond taking a fortress near Melitene: but the naval preparations were not given up, and in spring 655 Abul-Awar was sent to Phoenix in Lycia, a place celebrated for cypresses, to cut wood for shipbuilding, where he was joined by the Egyptian ships under Abdallah. But the new naval policy of the Arabs had forced the Romans also to institute a standing fleet; and the invaders were attacked by the Emperor in person, who was accompanied by his brother, Theodosius. In the battle which followed the Arabs were victorious, the Roman fleet being almost destroyed and Constans with difficulty escaping in disguise; but the Arabs, having attained their object, returned. Muawiya at the same time made an expedition by land as far as Caesarea; but in 656 the murder of Othman and the civil war which followed put an end to his schemes, and he was at last glad to buy peace by paying tribute (659). The Emperor used the respite to reduce some Slavonic tribes, some of which he transferred to Asia to assist in the defence against the Arabs…