emperor of the East, A. D. 641-668, the elder son of the emperor Constantine III. and the empress Gregoria, was born on the 7th of November, A. D. 630, and his original name was Heraclius. After the death of his father, who reigned but a few months, in A. D. 641, the throne was seized by Heracleonas, the younger brother of Constantine III.; but as Heracleonas was a tool in the hands of his ambitious mother, Martina, he incurred the hatred of the people, and a rebellion broke out, which was headed by Valentinus Caesar. Valentine at first compelled Heracleonas to admit his nephew Heraclius as co-regent, and on this occasion Heraclius adopted the name of Constantine, which he afterwards changed into that of Constans. Not satisfied with this result, Valentine proclaimed Constans sole emperor: Heracleonas and Martina were made prisoners, and, after being mutilated, were sent into exile. Thus Constans II. succeeded in the month of August, A. D. 641, and on account of his youth was obliged to be satisfied with only the name of emperor, and to abandon his authority to Valentine, who is probably identical with one Valentinian, who rebelled in A. D. 644, but was killed in a skirmish in the streets of Constantinople.

The reign of Constans II. is remarkable for the great losses which the empire sustained by the attacks of the Arabs and Longobards or Lombards. Egypt, and at last its capital, Alexandria, had been conquered by 'Amru, the general of the khalif 'Omar, towards the close of the reign of the emperor Heraclius, the grandfather of Constans. (A. D. 610 --641.) Anxious to regain possession of Alexandria, Constans fitted out an expedition against Egypt, and we are informed by the Chinese annalists, that he sent ambassadors to the emperor of China, Taisum, to excite him to a war against the Arabs, by whom the Chinese possessions in Turkistan were then infested. (Comp. De Guignes, Histoire générale des Huns, i. pp. 55, 56.) This emperor reigned from A. D. 627 till 650, and as the Christian religion was preached in China during his reign by Syrian monks, from which we may conclude that an intercourse existed between China and the Greek empire, the fact related by the Chinese annalists seems worthy of belief, especially as the danger from the Arabs was common to both the empires. When Manuel, the commander of the imperial forces, appeared with a powerful fleet off Alexandria, the inhabitants took up arms against the Arabic governor 'Othman, and with their assistance Manuel succeeded in taking the town. (A. D. 646.) But he maintained himself there only a short time. 'Amru approached with a strong army; he took the town by assault, and Manuel fled to Constantinople with the remnants of his forces. A considerable portion of Alexandria was destroyed, and the Greeks never got possession of it again. Encouraged by this success, the khalif 'Omar ordered his lieutenant 'Abdu-l-lah to invade the Greek possessions in northern Africa. 'Abdu-l-lah met with great success; he conquered and killed in battle Gregorius, the imperial governor of Africa, and the Greeks ceded to him Tripolitana, and promised to pay an annual tribute for the remaining part of the imperial dominions in Africa. This treaty was concluded without the consent of Constans, and although it was dictated by necessity, the emperor blamed and punished his officers severely, and shewed so much resentment against his subjects in Africa, that he took revenge upon them seventeen years afterwards, as is mentioned below.

While 'Abdu-l-lah was gaining these advantages in Africa, Mú'awiyah, who subsequently became khalif, drove the Greeks out of Syria, and, after conquering that country, sailed with a fleet of 1700 small craft to Cyprus, conquered the whole island, and imposed upon the inhabitants an annual tribute of 7200 pieces of gold. The island, however, was taken from the Arabs two years after the conquest, by the imperial general Cacorizus. The Arabs made also considerable progress in Cilicia and Isauria, which were ravaged by Bizr, one of their best generals. While the finest provinces of the East thus became a prey to the khalifs, the emperor was giving all his attention towards the protection of monothelism, to which sect he was addicted, and the persecution of the orthodox catholic faith. Unable to finish the religious contest by reasonable means, Constans issued an edict by which he prohibited all discussions on religious subjects, hoping thus to establish monothelism by oppressive measures. This edict, which is known by the name of " Typus," created as much discontent as laughter: it was rejected by the pope and generally by all the churches in Italy, and contributed much to ruin the emperor in public opinion. His subjects manifested publicly their contempt for his character, and the governors of distant provinces paid so little respect to his authority, that they seemed to be independent princes. A revolt broke out in Armenia under Pasagnathus, who made himself completely independent; but he afterwards returned to obedience.

As early as 648, a truce for two years had been concluded between the Arabs and Constans. 'Abdu-l-lah availed himself of that truce to invade and conquer Nubia and Abyssinia; but he returned in 651, renewed hostilities, and sent an expedition against Sicily, where the Arabs took several places, and maintained themselves there. In the same year Mú'awiyah spread terror through both the East and the West by the conquest of Rhodes, and it was on this occasion that the famous colossus was sold to a Jew of Edessa.

The fall of Rhodes failed to rouse Constans from his carelessness. He still endeavoured to compel obedience to his "Typus" in Italy, although it had been condemned by pope Martin I. Theodorus Calliopas, the imperial exarch in Italy, arrested Martin in his own palace in 653, and sent him from thence to Messina, afterwards to the island of Naxos, and at last, in 654, to Constantinople. Here, after a mock trial, he was condemned of holding treacherous correspondence with the infidels, and was mutilated and banished to Cherson, in the Chersonnesus Taurica, where he died in September, A. D. 655. Many other bishops of the orthodox faith were likewise persecuted, among whom was St. Maximus, who died in exile in the Caucasus, in 662.

In 655, the war with the Arabs became alarmingly dangerous. Mú'awiyah, then governor of Syria, fitted out a fleet, which he entrusted to the command of Abú-l-ábár, while he himself with the land forces marched against Caesareia, whence he intended to proceed to the Bosporus. In this imminent danger Constans gave the command of Constantinople to his eldest son, Constantine, and sailed himself with his own ships against the hostile fleet. The two fleets met off the coast of Lycia, and an obstinate battle ensued, in which the Greeks were at last completely defeated. Constantinople seemed to be lost. But the khalif 'Othmán was assassinated in 655, and Mú'awiyah, who was chosen in his stead, was obliged to renounce the conquest of Constantinople, and to defend his own empire against the attempts of 'Alí, and afterwards of his son Hasán, who assumed the title of khalif, and maintained themselves at Kufá till 668. Delivered from the Arabs, Constans made war upon the Slavonian nations south and north of the Danube with great success.

In 661, Constans put his brother Theodosius to death. The reasons for this crime are not well known; for, as Theodosius had taken orders, and was consequently unfit for reigning, political jealousy could not be the cause; perhaps there was some religious difference between the two brothers. The murder of his brother pressed heavily upon him ; he constantly dreamt about him, and often awoke, crying out that Theodosius was standing at his bedside, holding a cup of blood, and saying, " Drink, brother, drink !" His palace at Constantinople was insupportable to him, and he at last resolved to quit the East and to fix his residence in Italy. The political state of this country, however, was as strong a reason for the emperor's presence there as the visions of a murderer.

As early as A. D. 641, Rotharis, king of the Longobards, attacked the imperial dominions in northern Italy, and conquered the greater part of them. One of his successors, Grimoald, had formed designs against the Greek possessions in southern Italy, where the emperor was still master of the duchies of Rome and Naples, with both the Calabrias. Sicily, Sardinia, and Corsica belonged likewise to the Greek empire. The emperor's authority in Italy was much shaken by the religious and civil troubles which he had caused there by his absurd edict, the " Typus;" but, on the other hand, the dissensions among the dukes and other great chiefs of the Longobards seemed to afford a favourable chance for the re-establishment of the Roman empire of Italy by the Greeks, an enterprise which one hundred years before the emperor Justinian had so gloriously achieved by his general Narses. Under these circumstances, Constans resolved not only to imitate the example of Justinian, but to make Rome once more the centre of the Roman empire. His resolution caused the greatest surprise, for since the downfall of the Western empire no emperor had resided, nor even made a momentary stay, in Italy. " But," said Constans, " the mother (Rome) is worthier of my care than the daughter (Constantinople);" and, having fitted out a fleet, he fixed the day of his departure, and ordered the empress and his three sons to accompany him. He waited for them on board of his galley, but no sooner had they left the imperial palace, than the people of Constantinople rose in revolt and prevented them by force from joining the emperor. Being informed of this, Constans spit against the city, cursed its inhabitants, and ordered the sailors to weigh anchor. This took place towards the end of 662. Constans stayed the winter at Athens, having previously appointed his eldest son, Constantine, governor of Constantinople. Our space prevents us from giving an account of his campaign in Italy ; it is sufficient to state, that though he met at first with some success, his troops were afterwards defeated by the Longobards, and he was obliged to relinquish his design of subduing them. After plundering the churches and other public buildings of Rome of their finest ornaments and treasures, he took up his residence at Syracuse for a time. In this city also he gratified his love of avarice and cruelty to such an extent, that many thousands fled from the island and settled in different parts of Syria, especially at Damascus, where they adopted the religion of Mohammed. The emperor's absence from the seat of government excited Mú'awiyah to make fresh inroads into the Greek provinces.

It has been already related that Constans was deeply offended on account of the treaty having been concluded without his consent between his officers in Africa and the Arabian general 'Abdu-l-lah. In 665, Mú'awiyah being then chiefly occupied in the eastern part of the Khalifate, Constans resolved to revenge himself upon his subjects in Africa, and accordingly imposed a tribute upon them which was more than double what they had engaged to pay to the Arabs. This avaricious and imprudent measure caused a revolt. They invited the Arabs to take possession of their country, promising to make no resistance. Upon this Mú'awiyah entered Africa, defeated the few troops who were faithful to Constans, and extended his conquests as far as the frontiers of Mauretania. During the same time the Longobards extended their conquests in Italy. Despised and hated by all his subjects, Constans lost his life by the hand of an assassin, at least in a most mysterious manner, perhaps by the intrigues of orthodox priests. On the 15th of July, 668, he was found drowned in his bath at Syracuse. He left three sons, Constantine IV. Pogonatus, his successor, Heraclius, and Tiberius. The name of his wife is not known. (Theophanes, p. 275, &c., ed. Paris ; Cedrenus, p. 429, &c., ed. Paris; Zonaras, vol. ii. p. 87, &c., ed. Paris; Glycas, p. 277, &c., ed. Paris; Philo Byzantinus, Libellus de, Septem Orbis Spectaculis, ed. Orelli, Leipzig, 1816, pp. 15, &c., 30, &c., and the notes of Leo Allatius, p. 97, &c.; Paulus Diaconus (Warnefried), De Gestis Longobardorum, 4.51, &c., v. 6-13, 30; Abulfeda, Vita Mohammed, p. 109, ed. Reiske, Annales, p. 65, &c., ed. Reiske.)