1. Revolt and Accession of Herakleios (610 – 641)

Herakleios¹ was the son of the eponymous exarch of Carthage. While Herakleios the elder seems to have had no designs on the throne himself, he did instigate the rebellion with his son in 608. However, only his son seems to have gone on the expedition to Constantinople to overthrow the unpopular usurper Phokas, who had murdered the Emperor Maurice and his family.

Herakleios had the support of both the Greens and the church hierarchy in his overthrow of Phokas, but his reign was by no means a peaceful one. Herakleios’ reign was one of spectacular defeat, success, and still spectacular defeat again. Herakleios is a particularly difficult emperor to analyze. He was pivotal, yet sources are sometimes contradictory and not always clear. The historian must often result to conjecture.²

Although Herakleios had success and defeat, Byzantine sources are generally positive in the appraisal of his reign. In Arab sources, he achieves legendary status.³ Upon accession to the throne, the finances of the empire were in disarray and the Slavs and Avars were invading from the north while the Persians were attacking from the East. Eventually the Persians captured Jerusalem in 614 and occupied Egypt from ca. 619 to 629. Herakleios considered transferring the capital of the city to Carthage, but was dissuaded by the Patriarch Sergios I. In 626, Constantinople was besieged by a combined force of Avars and Persians, but the siege failed. Herakleios recruited and trained an army, and then invaded Persia from the North with Caucasian allies.⁴ By 627, the tide had turned and Herakleios was invading Persia. The Persians soon sued for peace.⁵ But victory proved ephemeral, as in 634 the Arabs invaded and defeated the Byzantine army in a crushing blow at Yarmuk in 636.

Herakleios sought stability in both the church and his private life, but he found it elusive. His attempts to achieve church unity through the doctrines of monoenergism and monotheletism only exacerbated the problem in both East and West. He married twice in order to achieve dynastic security, first to Fabia, who took the name Eudokia and died of epilepsy in 612, and then to his niece Martina in 622 or 623. In spite of the turmoil of his reign, the dynasty proved resilient. The marriage to his niece Martina proved to be highly unpopular. It required a dispensation from the Patriarch Sergios I and was seen as incestuous by the majority of Byzantines. Most of the children had health problems and died at an early age, perhaps as a result of consanguinity, but many, including Herakleios, assumed the deaths were on account of divine displeasure at such a match. Still, Herakleios remained devoted to Martina and their children. When he died in 641, he wished Herakleios Constantine, his eldest son from his first marriage and Heraklonas (Herakleios II), his surviving son from his second marriage to Martina, to rule as co-emperors with Martina as regent for Heraklonas. Heraklonas was born in 626 and was only fifteen at the time.

2. Death of Herakleios and Succession of Constans II (641 – 668)

Although Herakleios wished to include Martina and their offspring in the succession, the dynasty was to survive through the children of his first marriage to Eudokia. Herakleios Constantine, also known as Constantine III, was emperor for only a few months in 641, from 11 January to 24 May. He had been born 3 May 612 in Constantinople. Little is known about his childhood. He was proclaimed co-emperor 22 January 613, as his father Herakleios wished to secure the succession while he was on campaign and away from the capital. After the death of his father, he faced opposition from his step-mother Martina and the continued disaster of the Arab invasions. He was short of funds and the defense of Egypt failed. He died from poor health, although it was rumored that Martina poisoned him. Martina attempted to rule after the death of Herakleios Constantine, but was unpopular. She and her son were overthrown. Heraklonas’ nose was slit, and he and Martina were exiled to Rhodes in 642. Herakleios Constantine had married his cousin Gregoria, and their son, Constans II was proclaimed emperor after his father’s death.⁶ Heraklonas himself had proclaimed Constans co-emperor in an effort to share power, but Heraklonas and his family were removed anyway.

2.1. Constans II's reign

Constans II was born 7 November 630 and became sole emperor in 642, at the age of twelve. He ruled officially as Constantine, the name which also appears on the coins from his reign. However, he was popularly known as Constans. His father-in-law, the general Valentinos who overthrew Martina, was crowned co-emperor and was the actual ruler, which resulted to riots by the populace in 645, in favour of the legal heir. Valentine was killed and Constans, just 15 at the time, found himself sole Emperor.

Constans assumed power at a time when the empire was in a critical situation. After Herakleios' death, with Syria, Palestine and part of Mesopotamia having passed under Arab rule, and the destructive Persian Wars still recent, the State was nearly bankrupt and had no real leadership. With Armenia and Anatolia under Arab attacks, Byzantine Italy and Africa torn by revolts, and the Slavic pressure from North, the Empire was in grave danger. Thus, the young Emperor's main concern was the struggle against Arabs and the Slavs, though he was repeatedly defeated by the first and had limited success against the latter. After the loss of Armenia in 654 and the destructive attacks of the Arab fleet against Rhodes, Cyprus and Crete, it was only a civil war between the Arabs, resulting in a ceasefire with Byzantium, that offered the Empire some relief by the pressure.⁷

In 662, Constans left for Italy; he arrived there in 663 and set up his headquarters in Sicily. The revolts in Italy and Africa jeopardised the Byzantine rule there. Constans tried to raise an army and navy there to consolidate Byzantine control, but his effort was marked by highly unpopular ecclesiastical policies, especially in the matter of monotheletism. Not only did he refused to condemn it, but he also persecuted its adversaries, the Pope Martin I and St. Maximus the Confessor, who had supported revolts against him in Italy and Africa. Also his high taxations and confiscations made him extremely unpopular in the West. He faced a series of revolts and was finally murdered in his bath at Syracuse in 668, by the comes of Opsikion, Mezizius, who was afterwards proclaimed emperor. His body was returned to Constantinople where he was buried in the Church of the Holy Apostles.

3. Constantine IV (668 – 685)

Constantine IV,⁸ son of Constans II was born ca. 650. His father proclaimed him co-emperor in April 654. After his father’s murder, Constantine personally went to Sicily and defeated the usurper Mezizios. He ruled with his younger brothers Herakleios and Tiberios until 681, when he deposed and mutilated them, probably on account of a conspiracy. Throughout his reign, he sought diplomatic solutions to internal and external problems. He presided over the Council of Constantinople (681) to end the Monothelete controversy, and he secured peace with the Arabs, Lombards, and Bulgars. He died of dysentery in 685. His two sons, Justinian and Herakleios, as well as his wife Anastasia, survived him.

4. Justinian II (685 – 695; 705 – 711)

Justinian II was the last of the Heraclian dynasty,⁹ and his reign was as turbulent as that of his great-great grandfather. He was emperor twice, from 685-95 and 705-11. He was born in Constantinople ca. 688 and died in Damatrys 7 November 711. He had a daughter by his first wife Eudokia. Initially, Justinian II enjoyed victories against the Arabs with the general Leontios at the head of his armies. Justinian attempted reforms in both church and state. He was the first to include the image of Christ on coinage, and he began grand building projects that led to heavy taxation. Leontios overthrew him in 695, slit his nose, and exiled him to Cherson. There, Justinian married the Khazar khagan’s sister Theodora and sought the khagan’s aid to regain the throne. Ultimately he received aid from the Bulgar khan Tervel in 704. In 705, Tervel and Justinian overthrew Tiberios III. Justinian rewarded Tervel handsomely, proclaimed him Caesar, and may have given him his daughter in marriage. In Justinian’s second period as emperor he reportedly wore a gold nose to cover his mutilation. Justinian was leading an expedition against Cherson in 711 when the fleet revolted and proclaimed Philippikos emperor. Philippikos attacked Constantinople and forced Justinian to flee to Asia Minor. The general Elias pursued him there, captured him, and personally decapitated him and brought his head back to Constantinople. The fate of Theodora, the first foreign-born Byzantine empress, and their son, Tiberios, presumably heir apparent, is not clear, but one can assume that it was not peaceful. The dynasty effectively ends with the execution of Justinian II.

5. The Monothelete controversy

The recovery of the eastern provinces after the victory of Herakleios against the Persians once again raised the question of Monophysism. Ensuring pease in Church matters was of great importance to Herakleios, who wanted to avoid any centrifuge tendencies in the Eastern provinces. Thus, he supported the efforts of Patriarch Sergios to draw bridges over the gap between the doctrine of the two natures of Christ, confirmed by the IV Ecumenical Council at Chalcedon (451), and Monophysism. It was towards this direction that he endorsed the doctrine of one and the same energy possessed by both natures of Christ. However, despite the initial support of Sergios’s attempts by Cyrus, Patriarch of Alexandria, and Pope Honorius I, this compromise was met with great resistance; and so, in 638, under the pressure of Sophronius of Jerusalem’s challenges and the somewhat moderate stance of Pope Honorius, Sergios composed the text that Herakleios released as the edict Ekthesis. He essentially abandoned the formula of the one energy, proclaiming instead that Christ had only one will. But the emphasis of the edict was put upon discouraging any further exploration on the controversy, since the conciliatory attempt had already failed as regards the political stakes for Herakleios: in 638, Syria and Palestine had already been lost to the Arabs and Egypt was soon to follow.

The situation was difficult in the West and North Africa too. As Constans II supported the Monothelete doctrine, in North Africa the opposition to central authority was expressed through a series of local councils that condemned the doctrine as heretic. Maximus the Confessor, one of the greatest theologians of his days, was the leader of the orthodox party there. This controversy encouraged the attempt of the aspiring usurper Gregory, the exarch of Cathago, who in 646 proclaimed himself Emperor; however, he was defeated by the Arabs in the next year. North Africa remained under Byzantine control and Constans II strove to provide a solution issuing his Typos in 648, an edict that forbade any discussions upon the controversy but also ruled that Herakleios’s Ekthesis would be removed from the narthex of Hagia Sophia. But this only resulted in Italy following Africa’s example: Pope Martin I convened the Lateran council of 649, which condemned both the Ekthesis and the Typos. Even though the council’s formulations were carefully composed to avoid charging Emperors Herakleios and Constans II with heretical tendencies, Constans was quick to take action against Martin I. However, the exarch of Ravenna Olympius tried to take advantage of the resentment of Rome towards Constantinople in order to remove Italy from imperial control, while Constans II had his hands full in the East with the first naval campaign of Caliph Muawiyah I. The death of Olympius in 652 put an end to the revolt, and the next year Pope Martin I was condemned as guilty of high treason for his role in it. Maximos the Confessor had the same fate. The two leaders of the opposition to Motheletism died in exile after suffering torments and – in the case of Maximos – years of incarceration.

In the years of Constantine IV, with the Arabs consolidated in the East and the hope of resuming control over the former Eastern provinces lost for Byzantium, it became clear that insisting upon Monotheletism was of no more use. On the contrary, such policy was causing discord between Constantinople and the Western provinces. Thus, Constantine IV, after consulting Pope Agatho, convoked a council in Constantinople to condemn Monotheletism. This was the VI Ecumenical Council, which, after proceedings that lasted about a year, condemned Monotheletism and declared that Jesus Christ had two energies and two wills, corresponding to each one of his perfect natures. This was the resolution of the last major Christological controversy, which had disrupted the Empire for half a century and had marked the policy of the emperors of the Heraclian dynasty.¹⁰

6. The Empire under the Heraclian Dynasty

The Heraclian dynasty may be considered a success for its survivability. Herakleios and his successors faced the greatest threats that the Εmpire had ever faced, and yet they managed to keep a successful succession for five generations. However, ultimately the dynasty ended with violence, and individual emperors did not always respond to crises in the most effective way.

Apart from striving to retain power, the members of the Heraclian dynasty had to face the challenges of the transformation that the Empire went through during the 7th C. Successive invasions threatened the Empire's territorial integrity and the administrative system had to go through radical changes in order for the Byzantine defence in Asia Minor to be reinforced. After the defeat of the Sassanid Persians by Herakleios, who thus manged to restore Byzantium's eastern provinces, came the waves of Arab invasions, to which Byzantium soon lost North Africa; between 674 and 678 even Constantinople found itself under Arab siege. The establishment of the theme system proved crucial for the defence of Asia Minor, and it was only under Justinian II and Tiberios III that the eastern frontier was stabilised, although Arab incursions and Byzantine counterattack did not cease. The later 7th c. was marked by the rise of the Bulgars as an antagonist for the Empire and the establishment of their state in formerly imperial territory.

The 7th century also saw the eclipse of the urban centers of the late ancient world, with all the major changes in the social and economic structure of Mediterranean society that this eclipse entailed. Wars, plagues and the suppression of their economic indipendence led to the social, and in some cases physical, devastation of major cities. By the end of the Heraclian dynasty, the Byzantine state that had emerged was characterized by centralisation of tax-collection and the replacement of local centers of power by Constantinople (with a few urban centers surviving as emporia and ports); by agrarian economy and military-oriented administration.

Lastly, territorial losses and rearrangement of the frontiers resulted in a more homogeneous state, reduced to its mostly Greek-speaking and firmly Chalcedonian core lands.