After the peace of 628 the Roman and the Persian Empires, drained of men
 and money, and ravaged from end to end by each other's marauding armies,
 sank down in exhaustion to heal them of their deadly wounds. Never before
 had either power dealt its neighbour such fearful blows as in this last
 struggle: in previous wars the contest had been waged around border
 fortresses, and the prize had been the conquest of some small slice of
 marchland. But Chosroes and Heraclius had struck deadly blows at the heart
 of each other's empire, and harried the inmost provinces up to the gates
 of each other's capitals. The Persian had turned the wild hordes of the
 Avars loose on Thrace, and the Roman had guided the yet wilder Chazars up
 to the walls of Ctesiphon. Hence it came to pass that at the end of the
 war the two powers were each weaker than they had ever been before. They
 were bleeding at every pore, utterly wearied and exhausted, and desirous
 of nothing but a long interval of peace to recover their lost strength.
 
 Precisely at this moment a new and terrible enemy fell upon the two
 war-worn combatants, and delivered an attack so vehement that it was
 destined to destroy the ancient kingdom of Persia and to shear away half
 the provinces of the Roman Empire.
 
 The politics of Arabia had up to this time been of little moment either to
 Roman or Persian. Each of them had allies among the Arab tribes, and had
 sometimes sent an expedition or an embassy southward, into the land beyond
 the Syrian desert. But neither of them dreamed that the scattered and
 disunited tribes of Arabia would ever combine or become a serious danger.
 
 But while Heraclius and Chosroes were harrying each other's realms events
 of world-wide importance had been taking place in the Arabian peninsula.
 For the first and last time in history there had arisen among the Arabs
 one of those world-compelling minds that are destined to turn aside the
 current of events into new channels, and change the face of whole
 continents.
 
 Mahomet, that strangest of moral enigmas, prophet and seer, fanatic and
 impostor, was developing his career all through the years of the Persian
 war. By an extraordinary mixture of genuine enthusiasm and vulgar cunning,
 of self-deception and deliberate imposture, of benevolence and cruelty, of
 austerity and licence, he had worked himself and his creed to the front.
 The turbulent polytheists of Arabia had by him been converted into a
 compact band of fanatics, burning to carry all over the world by the force
 of their swords their new war-cry, that "God was God, and Mahomet His
 prophet."
 
 In 628, the last year of the great war, the Arab sent his summons to
 Heraclius and Chosroes, bidding them embrace Islam. The Persian replied
 with the threat that he would put the Prophet in chains when he had
 leisure. The Roman made no direct reply, but sent Mahomet some small
 presents, neglecting the theological bent of his message, and only
 thinking of enlisting a possible political ally. Both answers were
 regarded as equally unsatisfactory by the Prophet, and he doomed the two
 empires to a similar destruction. Next year [629] the first collision
 between the East-Romans and the Arabs took place, a band of Moslems having
 pushed a raid up to Muta, near the Dead Sea. But it was not till three
 years later, when Mahomet himself was already dead, that the storm fell on
 the Roman Empire. In obedience to the injunctions of his deceased master,
 the Caliph Abu Bekr prepared two armies, and launched the one against
 Palestine and the other against Persia.
 
 Till the last seven or eight years English writers have been inclined to
 underrate the force and fury of an army of Mahometan fanatics in the first
 flush of their enthusiasm. Now that we have witnessed in our own day the
 scenes of Tamaai and Abu Klea we do so no longer. The rush that can break
 into a British square bristling with Martini-Henry rifles is not a thing
 to be despised. For the future we shall not treat lightly the armies of
 the early Caliphs, nor scoff with Gibbon at the feebleness of the troops
 who were routed by them. If the soldiers of Queen Victoria, armed with
 modern rifles and artillery, found the fanatical Arab a formidable foe,
 let us not blame the soldiers of Heraclius who faced the same enemy with
 pike and sword alone. In the early engagements between the East-Romans and
 the Saracens the superior discipline and more regular arms of the one were
 not a sufficient counterpoise to put against the mad recklessness of the
 other. The Moslem wanted to get killed, that he might reap the fruits of
 martyrdom in the other world, and cared not how he died, if he had first
 slain an enemy. The Roman fought well enough; but he did not, like his
 adversary, yearn to become a martyr, and the odds were on the man who held
 his life the cheapest.
 
 The moment of the Saracen invasion was chosen most unhappily for
 Heraclius. He had just paid off the enormous debt that he had contracted
 to the Church, and to do so had not only drained the treasury but imposed
 some new and unwise taxes on the harassed provincials, and disbanded many
 of his veterans for the sake of economy. Syria and Egypt, after spending
 twelve and ten years respectively under the Persian yoke, had not yet got
 back into their old organization. Both countries were much distracted with
 religious troubles; the heretical sects of the Monophysites and Jacobites
 who swarmed within their boundaries had lifted up their heads under the
 Persian rule, being relieved from the governmental repression that had
 hitherto been their lot. They seem to have constituted an actual majority
 of the population, and bitterly resented the endeavours of Heraclius to
 enforce orthodoxy in the reconquered provinces. Their discontent was so
 bitter that during the Saracen invasion they stood aside and refused to
 help the imperial armies, or even on occasion aided the alien enemy.
 
 The details of the Arab conquest of Syria have not been preserved by the
 East-Roman historians, who seem to have hated the idea of recording the
 disasters of Christendom. The Moslems, on the other hand, had not yet
 commenced to write, and ere historians arose among them, the tale of the
 invasion had been intertwined with a whole cycle of romantic legends,
 fitter for the "Arabian Nights" than the sober pages of a chronicle.
 
 But the main lines of the war can be reconstructed with accuracy. The
 Saracen horde under Abu Obeida emerged from the desert in the spring of
 634 and captured Bostra, the frontier city of Syria to the east, by the
 aid of treachery from within. The Romans collected an army to drive them
 off, but in July it was defeated at Aijnadin [Gabatha] in Ituraea.
 Thoroughly roused by this disaster Heraclius set all the legions of the
 East marching, and sixty thousand men crossed the Jordan and advanced to
 recover Bostra. The Arabs met them at the fords of the Hieromax, an
 Eastern tributary of the Jordan, and a fierce battle raged all day. The
 Romans drove the enemy back to the very gates of their camp, but a last
 charge, headed by the fierce warrior Khaled, broke their firm array when a
 victory seemed almost assured. All the mailed horsemen of Heraclius, his
 Armenian and Isaurian archers, his solid phalanx of infantry, were
 insufficient to resist the wild rush of the Arabs. Urged on by the cry of
 their general, "Paradise is before you, the devil and hell-fire behind,"
 the fanatical Orientals threw themselves on regiment after regiment and
 drove it off the field.
 
 All Syria east of Jordan was lost in this fatal battle. Damascus, its
 great stronghold, resisted desperately but fell early in 635. Most of its
 population were massacred. This disaster drew Heraclius into the field,
 though he was now over sixty, and was beginning to fail in health. He
 could do nothing; Emesa and Heliopolis were sacked before his eyes, and
 after an inglorious campaign he hurried to Jerusalem, took the "True
 Cross" from its sanctuary, where he had replaced it in triumph five years
 before, and retired to Constantinople. Hardly had he reached it when the
 news arrived that his discontented and demoralized troops had proclaimed a
 rebel emperor, though the enemy was before them. The rebel--his name was
 Baanes--was put down, but meanwhile Antioch, Chalcis, and all Northern
 Syria fell into the hands of the Arabs.
 
 Worse yet was to follow. In the next year, 637, Jerusalem fell, after a
 desperate resistance, protracted for more than twelve months. The
 inhabitants refused to surrender except to the Caliph in person, and the
 aged Omar came over the desert, proud to take possession of the city which
 Mahomet had reckoned the holiest site on earth save Mecca alone. The
 Patriarch Sophronius was commanded to guide the conqueror around the city,
 and when he saw the rude Arab standing by the altar of the Church of the
 Holy Sepulchre, cried aloud, "Now is the Abomination of Desolation, which
 was spoken of by Daniel the prophet, truly in the Holy Place." The Caliph
 did not confiscate any of the great Christian sanctuaries, but he took the
 site of Solomon's Temple, and erected on it a magnificent Mosque, known
 ever since as the Mosque of Omar.
 
 The tale of the last years of Heraclius is most melancholy. The Emperor
 lay at Constantinople slowly dying of dropsy, and his eldest son
 Constantine had to take the field in his stead. But the young prince
 received a crushing defeat in 638, when he attempted to recover North
 Syria, and next year the Arabs, under Amrou, pressed eastward across the
 Isthmus of Suez, and threw themselves upon Egypt. Two years more of
 fighting sufficed to conquer the granary of the Roman Empire; and in
 February, 641, when Heraclius died, the single port of Alexandria was the
 sole remaining possession of the Romans in Egypt.
 
 The ten years' war which had torn Syria and Egypt from the hands of the
 unfortunate Heraclius had been even more fatal to his Eastern neighbour.
 The Arabs had attacked the Persian kingdom at the same moment that they
 fell on Syria: two great battles at Kadesia [636] and Yalulah [637]
 sufficed to place all Western Persia in the hands of the Moslems. King
 Isdigerd, the last of the Sassanian line, raised his last army in 641, and
 saw it cut to pieces at the decisive field of Nehauend. He fled away to
 dwell as an exile among the Turks, and all his kingdom as far as the
 borders of India became the prey of the conquerors.
 
 Heraclius had married twice; by his first wife, Eudocia, he left a single
 son, Constantine, who should have been his sole heir. But he had taken a
 second wife, and this wife was his own niece Martina. The incestuous
 choice had provoked much scandal, and was the one grave offence which
 could be brought against Heraclius, whose life was in other respects
 blameless. Martina, an ambitious and intriguing woman, prevailed on her
 aged husband to make her eldest son, Heracleonas, joint-heir with his half
 brother Constantine.
 
 This arrangement, as might have been expected, worked very badly. The
 court and army was at once split up between the adherents of the two young
 Emperors, and while the defence of the empire against the Saracens should
 have been the sole care of the East-Romans, they found themselves
 distracted by fierce Court intrigues. Armed strife between the Emperors
 seemed destined to break out, but after reigning only a few months
 Constantine III. died. It was rumoured far and wide that his step-mother
 had poisoned him, to make the way clear for her own son Heracleonas, who
 immediately proclaimed himself sole emperor. The senate and the Byzantine
 populace were both highly indignant at this usurpation, for the deceased
 Constantine left a young son named Constans, who was thus excluded from
 the throne to which he was the natural heir. Heracleonas had reigned alone
 no more than a few weeks when the army of the East and the mob of
 Constantinople were heard demanding in angry tones that Constans should be
 crowned as his uncle's colleague. Heracleonas was frightened into
 compliance, but his submission only saved him for a year. In the summer of
 642 the senate decreed his deposition, and he was seized by the adherents
 of Constans and sent into exile, along with his mother Martina. The
 victorious faction very cruelly ordered the tongue of the mother and the
 nose of the son to be slit--the first instance of that hateful Oriental
 practice being applied to members of the royal house, but not the last.
 
 Constans II. was sole emperor from 642 to 668, and his son and successor,
 Constantine IV., reigned from 668 to 685. They were both strong,
 hard-headed warrior princes, fit descendants of the gallant Heraclius.
 Their main credit lies in the fact that they fought unceasingly against
 the Saracen, and preserved as a permanent possession of the empire nearly
 every province that they had still remained Roman at the death of
 Heraclius. During the minority indeed of Constans II., Alexandria and
 Aradus, the two last ports preserved by the Romans in Egypt and Syria were
 lost. But the Saracens advanced no further by land; the sands of the
 African desert and the passes of Taurus were destined to hold them back
 for many years. The times, however, were still dangerous till the murder
 of the Caliph Othman in 656, after which the outbreak of the first civil
 war among the Moslems--the contest of Ali and Moawiah for the
 Caliphate--gave the empire a respite. Moawiah, who held the lands on the
 Roman frontier--his rival's power lying further to the east--secured a free
 hand against Ali, by making peace with Constans. He even consented to pay
 him a small annual subsidy so long as the truce should last. This
 agreement was invaluable to the empire. After twenty-seven years of
 incessant war the mangled realm at last obtained an interval of repose. It
 was something, too, that the Saracens were induced to pause, and saw that
 the extension of their conquests was not destined to spread at once over
 the whole world. When they realized that their victories were not to go on
 for ever, they lost the first keenness of the fanatical courage which had
 made them so terrible.
 
 Freed from the Saracen war, which had threatened not merely to curtail,
 but to extinguish the empire, Constans was at liberty to turn his
 attention to other matters. It seems probable that it was at this moment
 that the reorganization of the provinces of the empire took place, which
 we find in existence in the second half of the seventh century. The old
 Roman names and boundaries, which had endured since Diocletian's time, now
 disappear, and the empire is found divided into new provinces with strange
 denominations. They were military in their origin, and each consisted of
 the district covered by a large unit of soldiery--what we should call an
 army corps. "Theme" meant both the corps and the district which it
 defended, and the corps-commander was also the provincial governor. There
 were six corps in Asia, called the Armeniac, Anatolic, Thracesian,
 Bucellarian, Cibyrrhaeot, and Obsequian themes. Of these the first two
 explain themselves, they were the "army of Armenia" and the "army of the
 East"; the Obsequian theme, quartered along the Propontis, was so called
 because it was a kind of personal guard for the Emperor and the home
 districts. The Thracesians were the "Army of Thrace," who in the stress of
 the war had been drafted across to Asia to reinforce the Eastern troops.
 The Bucellarii seem to have been corps composed of natives and barbarian
 auxiliaries mixed; they are heard of long before Constans, and he probably
 did no more than unite them and localize them in a single district. The
 Cibyrrhaeot theme alone gets its name from a town, the port of Cibyra in
 Pamphylia, which must have been the original headquarters of the
 South-Western Army Corps. Its commander had a fleet always in his charge,
 and his troops were often employed as marines.
 
 The western half of the empire seems to have had six "Themes" also; they
 bear however old and familiar names--Thrace, Hellas, Thessalonica, Ravenna,
 Sicily, and Africa, and their names explain their boundaries. In both
 halves of the empire there were, beside the great themes, smaller
 districts under the command of military governors, who had charge of
 outlying posts, such as the passes of Taurus, or the islands of Cyprus and
 Sardinia. Some of these afterwards grew into independent themes.
 
 Thus came to an end the old imperial system of dividing military authority
 and civil jurisdiction, which Augustus had invented and Diocletian
 perpetuated. Under stress of the fearful Saracenic invasion the civil
 governors disappear, and for the future a commander chosen for his
 military capacity has also to discharge civil functions.
 
 Constans II., when once he had made peace with Moawiah, would have done
 well to turn to the Balkan Peninsula, and evict the Slavs from the
 districts south of Haemus into which they had penetrated during the reign
 of Heraclius. But he chose instead to do no more than compel the Slavs to
 pay homage to him and give tribute, and set out to turn westward, and
 endeavour to drive the Lombards out of Italy. Falling on the Duchy of
 Benevento, he took many towns, and even laid siege to the capital. But he
 failed to take it, and passed on to Rome, which had not seen the face of
 an emperor for two hundred years. When an emperor did appear he brought no
 luck, for Constans signalized his visit by taking down the bronze tiles of
 the Pantheon and sending them off to Constantinople [664].
 
 The Emperor lingered no less than five years in the West, busied with the
 affairs of Italy and Africa, till the Constantinopolitans began to fear
 that he would make Rome or Syracuse his capital. But in 668 he was
 assassinated in a most strange manner. "As he bathed in the baths called
 Daphne, Andreas his bathing attendant smote him on the head with his
 soap-box, and fled away." The blow was fatal, Constans died, and
 Constantine his son reigned in his stead.
 
 Constantine IV., known as Pogonatus, "the Bearded," reigned for seventeen
 years, of which more than half were spent in one long struggle with the
 Saracens. Moawiah, the first of the Ommeyades, had now made himself sole
 Caliph; the civil wars of the Arabs were now over, and once more they fell
 on the empire. Constantine's reign opened disastrously, with simultaneous
 attacks by the armies and fleets of Moawiah on Africa, Sicily, and Asia
 Minor. But this was only the prelude; in 673 the Caliph made ready an
 expedition, the like of which had never yet been undertaken by the
 Saracens. A great fleet and land army started from Syria to undertake the
 siege of Constantinople itself, an enterprise which the Moslems had not
 yet attempted. It was headed by the general Abderrahman, and accompanied
 by Yezid, the Caliph's son and heir. The fleet beat the imperial navy off
 the sea, forced the passage of the Dardanelles, and took Cyzicus. Using
 that city as its base, it proceeded to blockade the Bosphorus.
 
 The great glory of Constantine IV. is that he withstood, defeated, and
 drove away the mighty armament of Moawiah. For four years the investment
 of Constantinople lingered on, and the stubborn resistance of the garrison
 seemed unable to do more than stave off the evil day. But the happy
 invention of fire-tubes for squirting inflammable liquids (probably the
 famous "Greek-fire" of which we first hear at this time), gave the
 Emperor's fleet the superiority in a decisive naval battle. At the same
 time a great victory was won on land and thirty thousand Arabs slain.
 Abderrahman had fallen during the siege, and his successors had to lead
 back the mere wrecks of a fleet and army to the disheartened Caliph.
 
 It is a thousand pities that the details of this, the second great siege
 of Constantinople, are not better known. But there is no good contemporary
 historian to give us the desired information. If he had but met with his
 "sacred bard," Constantine IV. might have gone down to posterity in
 company with Heraclius and Leo the Isaurian, as the third great hero of
 the East-Roman Empire.
 
 The year after the raising of the great siege, Moawiah sued for peace,
 restored all his conquests, and offered a huge war indemnity, promising to
 pay 3000 lbs. of gold per annum for thirty years. The report of the
 triumph of Constantine went all over the world, and ambassadors came even
 from the distant Franks and Khazars to congratulate him on the victory
 which had saved Eastern Christendom from the Arab.
 
 While Constantine was defending his capital from the Eastern enemy, the
 wild tribes of his northern border took the opportunity of swooping down
 on the European provinces, whose troops had been drawn off to resist the
 Arabs. The Slavs came down from the inland, and laid siege for two years
 to Thessalonica, which was only relieved from their attacks when
 Constantine had finished his war with Moawiah. But a far more dangerous
 attack was made by another enemy in the eastern part of the Balkan
 Peninsula. The Bulgarians, a nomad tribe of Finnish blood, who dwelt in
 the region of the Pruth and Dniester, came over the Danube, subdued the
 Slavs of Moesia, and settled between the Danube and the Eastern Balkans,
 where they have left their name till this day. They united the scattered
 Slavonic tribes of the region into a single strong state, and the new
 Bulgarian kingdom was long destined to be a troublesome neighbour to the
 empire. The date 679 counts as the first year of the reign of Isperich
 first king of Bulgaria. Constantine IV. was too exhausted by his long war
 with Moawiah to make any serious attempt to drive the Bulgarians back over
 the Danube, and acquiesced in the new settlement.
 
 The last six years of Constantine's reign were spent in peace. The only
 notable event that took place in them was the meeting at Constantinople of
 the Sixth Oecumenical Council in 680-1. At this Synod, the doctrine of the
 Monothelites, who attributed but one will to Our Lord, was solemnly
 condemned by the united Churches of the East and West. The holders of
 Monothelite doctrines, dead and alive, were solemnly anathematised, among
 them Pope Honorius of Rome, who in a previous generation had consented to
 the heresy.
 
 Constantine IV. died in 685, before he had reached his thirty-sixth year,
 leaving his throne to his eldest son Justinian, a lad of sixteen.