At this point we have to note that the Hellenic element in the state had definitely gained the upper hand before the end of the 6th century, so that henceforward the Empire might be described as Greek. Justinian’s mother-tongue was Latin, and he was devoted to the Latin traditions of Rome, but even he found it necessary to publish his later laws in Greek, and from his reign Greek was the official language.
Many of the Latin official terms were already represented by Greek equivalents (ὕπατος = consul, ἔπαρχος = praefectus, &c.), but they were preserved in great numbers, transliterated and often corrupted (e.g. κόμης, μάγιστρος, ἀσηκρήτης = a secretis, καγκελλάριος, πραιπόσιτος, κυέστωρ = quaestor, σάκρον παλάτιον, ὀφφίκιον, ὀψίκιον = obsequium). Ῥήξ, rex, was always used of barbarian potentates, βασιλεύς being reserved as = the emperor (but also applied to the Persian king). In military drill many Latin words of command continued to be used.
It is to be noted that the year 630 marks the beginning of a period of literary (and artistic) sterility in the Greek world (see Greek Literature, section Byzantine).
With the rise of Islam (see Caliphate; Mahomet) two universal religions, for the first time, stood face to face, each aspiring to win the universe. The struggle therefore which then began was not only a new phase of the “Eternal Question,” the strife between Europe and Asia, but was one in which the religious element was fundamental. Fire-worship was only a national religion and did not present the danger of Islam. The creation of the political power of the Mahommedans was so sudden that it took the world by surprise. Bostra, the fortress of Roman Arabia, fell into their hands in 634, and before the death of Heraclius in 641 they had conquered Syria and all Egypt, except Alexandria, which opened its gates to them in 643. The religious alienation of the Syrian and Egyptian peoples from Constantinople, expressing as it did a national sentiment antagonistic to the Greeks, was an important political factor in the Mahommedan (as in the previous Persian) conquest. Thus the Mahommedans definitely cut the Empire short in the East, as the Germans had cut it short in the West; Egypt was never recovered, Syria only for short periods and partially, while the integrity of Asia Minor was constantly menaced and Cilicia occupied for many generations. By their conquest of Persia the Caliphs succeeded to the position of the Sassanids; this led to the conquest of Armenia (c. 654); while, in the West, Africa was occupied in 647 (though the conquest was not completed till the capture of Carthage and other strong places in 698). Thus within twenty years from the first attack the Empire was girt about by the new aggressive power from the precincts of the Caucasus to the Western Mediterranean.
Fortunately Constans II., grandson of Heraclius, was a man of eminent ability and firmness. The state owed to him the preservation of Asia Minor, and the creation of a powerful fleet (see below) which protected the Aegean coasts and islands against the naval power which the Mahommedans created. He was responsible for completing a new, efficient military organization, which determined the lines of the administrative reforms of Leo III. (see below). In his last years he turned his eyes to Italy and Africa. He dreamed of restoring Old Rome as the centre of the Empire. But he did not succeed in recovering south Italy from the Lombards (Duchy of Beneventum), and having visited Rome he took up his residence in Syracuse, where he was assassinated, having lost two fleets which he sent against the Arabs of Africa. The strain lasted for another fifty years. Constantinople sustained two great sieges, which stand out as crises, for, if in either case the enemy had been successful, the Empire was doomed.
The first siege was in 673–77, under the caliph Moawiya; his fleet blockaded the capital for five years, but all its efforts were frustrated by the able re cautions of Constantine IV.; “Greek fire” (see below) played an important part in the defence; and the armada was annihilated on the voyage back to Syria by storms and the Roman fleet. The second crisis was at the accession of Leo III., when the city was besieged by land and sea by Suleiman for a year (717–18), and Leo’s brilliant defence, again aided by Greek fire, saved Eurpoe. This crisis marks the highest point of Mahommedan aggression, which never again caused the Empire to tremble for its existence.
The Heraclian dynasty, which had fallen on evil times and rendered inestimable services to the Empire, came to an end in anarchy, which was terminated by the elevation of the Syrian, (commonly called Isaurian) Leo III., whose reign opens a new period. His reforming hand was active in every sphere of government, but the ill-fame which he won by his iconoclastic policy obscured in the memory of posterity the capital importance of his work. His provincial organization was revolutionary, and his legislation departed from the Roman tradition (see below). From his reign to the middle of the 10th century the continuous warfare by land with the Caliphs consisted of marauding expeditions of each power into the other’s territory, captures of fortresses, guerilla lighting, but no great conquests or decisive battles. The efficiency of the army was carefully maintained, but the neglect of the navy led to the losses of Crete (conquered by Moslem adventurers from Spain 826) and Sicily (conquered by the Saracens of Africa), Panormus taken 832, Syracuse 878 (see Sicily). The Africans also made temporary conquests, including Bari, in south Italy. This period saw the loss of the exarchate of Ravenna to the Lombards (750), the expansion of the Frankish power under Pippin and Charlemagne in Italy, and in close connexion therewith the loss of Old Rome.
The iconoclast emperors pursued a moderate foreign policy, consolidating the Empire within its contracted limits; but under the “Macedonian” dynasty, which was of Armenian descent, it again expanded and became the strongest power in Europe. The 9th century also witnessed a revival of learning and culture which had been in eclipse for 200 years. The reign of Basil I. was marked by an energetic policy in south Italy, where his forces co-operated with the western emperor Louis II. The Saracens were expelled from their strongholds, Bari recovered, Calabria saved, and the new province (Theme) of Longibardia formed. This secured the entrance to the Adriatic, and the increase of dominion here at the expense of the Lombards was a compensation for the loss of Sicily. Leo VI. did much for reorganizing the navy, but his reign was not fortunate; Saracen pirates plundered freely in the Aegean and, under the able renegade Leo of Tripolis, captured Thessalonica and carried off countless captives (904). But a great tide of success began fifty years later. Nicephorus Phocas won back Crete (961) as general of Romanus II., and then as emperor recovered Cilicia and North Syria (with Antioch) 968. Cyprus was also recovered. The tide flowed on under his equally able successor, John Zimisces (of Armenian race) and under Basil II.; these reigns mark the decisive victory of the Empire in the long struggle with the Saracens, whose empire had been broken up into separate states. The eastern frontier was strengthened by the active policy of Basil II. in Armenia, which was more fully incorporated in the Empire under Constantine IX.
The reign of Basil II. marks the culmination of the power of the Eastern Empire, for it also witnessed the triumphant conclusion of another conflict which had lasted almost as long. In the reign of Constantine IV. the Bulgarians (see Bulgaria) had founded a kingdom in Lower Moesia, reducing the Slavonic tribes who had occupied the country, but less than two centuries sufficed to assimilate the conquerors to the conquered, and to give Bulgaria the character of a Slavonic state. The reign of Constantine V. was marked by continuous war with this enemy, and Nicephorus I. lost his life in a Bulgarian campaign. This disaster was followed up by Prince Krum, who besieged Constantinople in 815. His death was followed by a long peace. Prince Boris was converted to Christianity (reign of Michael III.); a metropolitan see of Bulgaria was founded, dependent on the patriarch of Constantinople; and the civilization of the Bulgarians, and beginnings of their literature, were entirely under Byzantine influence. The conversion was contemporary with the work of the two missionaries Cyril and Methodius, who (while the field of their personal activity was in Great Moravia and
