The defense of the conquered territories not only strained the resources of the empire in North Africa. The constant threat, much more so in Italy by the Lombards and in southern Spain by the Visigoths, forced the Eastern Romans to decentralize civil and military power in the conquered areas, especially since the old empire was defending itself against the Avars and Slavs in the Balkans and again since 572 of the Persian Sassanids in Asia Minor, Armenia and Syria was also exposed to some threats in his heartland. Securing the eastern provinces, which were richer, and much more directly connected to security of Constantinople itself, had to take precedence over holding the western possessions. Under these conditions, Maurice created the exarchates of Carthage and Ravenna in order to grant his governors the greatest possible freedom of action in these areas, which were now largely left to themselves. In doing so, he granted them the powers of de facto
viceroys. While civil and military powers had been separated since the early 4th century in the
Later Roman Empire and this principle was maintained in the original – i.e. assigned to Eastern half at the time of partition – Byzantine land, until the mid-7th century with the introduction of
theme system, this principle was now abandoned in the western possessions. This bundling of powers along with the obviously stable conditions in the economically strongest province of the former western empire led to a momentum of its own, which – favored by chaotic conditions in other parts of the empire – led to revolts against the imperial central authority in Constantinople. This development came to an end with the appearance of the Arabs, around half a century before the definitive end of Byzantine rule on the African continent.
The Exarchate between 591 and 642 The Exarchate under Maurice of
Heraclius, the Exarch of Carthage, dating to 608 and depicting him with his namesake son as Consul. In the province of Africa, the separation of civil and military powers was repeatedly broken due to warlike events during Justinian I's lifetime, especially in the case of Solomon as
praetorian prefect and Gennadius as
magister militum. In this respect, the founding of the exarchates by Maurice was merely an institutionalization of what had already proven itself in times of crisis. The founding of the Exarchate in Africa meant that Gennadius was also given the rest of the civil powers of the Praetorian Prefect and that this office was now subordinated to the Exarch – a process that must have taken place between May 6, 585 and July 591. Gennadius was able to achieve victories against the Berbers during his tenure as the first exarch (591-598), in 591 and in
Tripolitania in 595. This, coupled with his earlier victory over Altava, brought decades of peace and prosperity to the province of Africa. This is at least obvious because of the lack of contrary records or corresponding archaeological finds from the period. In addition, today's Maghreb was already a region in classical Roman times whose long border had to be secured with just one legion and has always been considered unproblematic. Only a new plague epidemic in 599/600 is mentioned in the written sources, which was probably less serious than the first wave of the "
Justinianic Plague". It is also known that at the end of the sixth century the region of Tripolitania was detached from the Exarchate of Carthage and annexed to
Byzantine Egypt. Due to the overall situation in Africa, Emperor Maurice had his back free to negotiate an advantageous peace with Persia (see
Roman-Persian War of 572-591) and then to oppose the Avars and Slavs (see
Maurice's Balkan campaigns).
The Exarchate during the last Roman-Persian War Even when the
most devastating of all Roman-Persian wars broke out and the situation in large parts of the empire deteriorated massively under Emperor
Phocas, conditions in Africa were much more stable. Heraclius the Elder, presumably the successor of Gennadios and probably appointed exarch by Maurice at the age of over 60, could mint coins and hire mercenaries. During this period only remote Septem could have been (temporarily) conquered by the Visigoths (616). Heraclius the Elder was initially involved – possibly in association with the
Sanhāja and
Zanata – in battles against other Berber tribes – especially near the Aurès and possibly also near the former kingdom of Altava. When Heraclius the Elder and his namesake son Heraclius
revolted against the emperor in 608, they first fanned dissatisfaction with Phocas in
Constantinople by imposing an embargo on grain and (olive) oil and significantly reducing the capital's supply of these staple foods. Then, in the fall of 609, they sent
their nephew/cousin Niketas to Egypt with an army, which he brought under his control in the spring of 610. In the spring/summer of 610, Heraclius (the younger) sailed to Constantinople with a fleet mostly manned by Berbers, where he overthrew Phocas from October 2 to 5, 610 and had him publicly executed. What is remarkable about this usurpation is that Africa could be stripped of its troops without immediately coming into military danger – a situation that would have been unthinkable in the
Moorish wars of 533-548. A few years later, during the last and greatest Persian war (603 to 628) Heraclius – facing Persian troops on the Asian side of the
Bosphorus – considered to move the capital of the empire from Constantinople to Carthage. This impressively demonstrates the stability and power of the Exarchate of Africa at this time. However, the emperor was dissuaded from these plans by
Sergios I, the
Patriarch of Constantinople. As the war progressed, the Persian Sassanid Empire
occupied Egypt, including Cyrenaica, for a good decade, but the Persians did not advance to Tripolitania, probably due to a lack of the necessary logistical capacities and the ability to operate in desert terrain. Constantinople, on the other hand,
defied its first siege in 626 and Heraclius finally defeated the Sassanids in 627/628, which also removed the temporary threat to the Exarchate of Carthage. Otherwise little is known about the conditions in Byzantine Africa until 633, which was certainly due to the temporary conquests of the Persians and the more final ones of the Arabs in the eastern Mediterranean and the associated effects on the corresponding sales markets have been accelerated.
Defence against the Arabs As a part of the Islamic expansion, Byzantine rule in the Maghreb came to an end after tough fighting. Unlike in
Asia Minor, where the Arab attacks ultimately repelled, the southern half of the Mediterranean was conquered by the Arabs within a good half a century. Responsible for this were insufficient precautions, an essentially defective coordination with Berbers and the Byzantine heartland – which against the background of the Monothelite disputes – which included the African resistance to imperially decreed forced conversions of Jews – culminating in a failed secession – and, to a lesser extent, geography. The process was also spurred by the struggles of the empire in the other provinces, in particular a strong Arab pressure on Asia Minor, but also the invasion of the
Proto-Bulgarians in the
Lower Danubian provinces are significant. It is also believed that the Byzantine fortresses, smaller than predecessors in pre-Vandal Roman times, were only effective against tribal uprisings and Berber attacks, but not against larger armies, This point contributed to the rapid Arab successes quite significantly.
Early invasions Africa was first confronted with Islamic expansion in 633, when Peter, the Exarch of Carthage, is said to have defied an order from Heraclius, on the advice of the Greek monk
Maximus Confessor, to send troops to support the defensive battle in Egypt. Even after
the conquest of Egypt by the Arabs, the exarchate probably still did not take the threat seriously enough. It is highly probable that being spared Persian invasion and the overestimation of the inhospitable terrains between Egypt and the Exarchate (especially the Surt) were the cause. Refugees from Egypt were also known from
the time of the occupation by Persian troops. The Exarchate was unprepared for defense against a land attack from the east. No forts were built on the border of Tripolitania, part of Byzantine Egypt, comparable to the
Mareth Line used in the African campaign of
World War II. An operative concept for a successful fight against the Arabs was still being sought throughout the empire. The first Arab expeditions were led by the Emir
Amr ibn al-As and his nephew ʿ
Uqba ibn Nafiʿ in 642/43 from the newly conquered Egypt to the west. Advances into Cyrenaica and Tripolitania met little resistance, anyway, the Byzantine control was limited to a few coastal bases, from which
Oea (today
Tripoli) and
Sabratha were plundered, the siege of Oea seems to have taken a long time. After the Arabs conquered
Alexandria again and forever in 646, the Byzantine Empire's weakness in the southern Mediterranean became apparent. The resulting domino effect seems to have been misunderstood in Carthage as an exclusive problem for Egypt and the old empire in general, despite a significant number of refugees from Egypt, which had also included Tripolitania for around 50 years. This was probably still favored by the greater attention paid to previous enemies, here the
Lombards and their conquest of
Liguria from 643, and by the need for the Arab troops to reorganize themselves after the storming of Tripolitania, especially from a logistical point of view. In 646 the Exarch
Gregory the Patrician, son of aforementioned Nicetas, thus also a member of
Heraclian Dynasty, rebelled against the emperor, also against the background of the monothelite disputes in Byzantium and in the alleged misconception that fighting between Arabs and Byzantines in Egypt would deter either side from attacking Africa. He decided to secede from Constantinople and moved the capital of exarchate to Sufetula/Sbeitla. According to Arabic sources, his power was so great that he was able to gather around 100,000 Berber soldiers, which was hardly realistic. The Arabs, meanwhile, had probably learned of Heraclius' failed plan in 633 to detach troops from Africa to defend Egypt, and probably wanted to avoid such a plan being carried out in the future. They bypassed
Oea, which had once again braced itself against an Arab siege, and invaded the exarchate from Tripolitania, which had been spared major fighting for almost 100 years. The rebellious exarch Gregory rallied his own troops and allies to the new capital of
Sufetula, but without support from the central government in Constantinople. According to Arabic sources, when he faced the Arabs led by
Abd Allah ibn Sa'd for battle, he was able to mobilize 120,000 to 200,000 men (which, like many such high figures, is probably clearly exaggerated for logistical reasons alone), but lost the
battle and possibly his life. The Arabs then ravaged
Byzacena within the next 12 to 15 months.
Tribute payments and renewed attacks The Arabs retreated to Tripolitania in 648 after receiving a large ransom, which increased their desires for this rich province and thus, in the long run, served the opposite purpose. Under the new exarch
Gennadios II, Byzantine supremacy was restored and the capital of the exarchate was moved back to Carthage, especially since Gregory had only moved the administrative seat inland to Sufetula out of fear of a punitive Byzantine expedition by sea. Nevertheless, due to the temporary secession, there remained a longer-term loss of confidence in Africa that went beyond the general distrust of the emperor. Byzantine rule was restored in the areas of the Exarchate overrun by the Arabs, but the extent of this repossession is debatable. Meanwhile, the
Byzantine fleet was attacking Muslim areas on the Eastern Mediterranean coast and even recapturing the
Barka region in
Cyrenaica, those naval activities coming to an end at the latest after the
Battle of the Masts in 655 respectively. The new exarch attempted to pacify the Arabs by paying tribute, presumably under the mistaken belief that the Arabs, like the Berbers, were not interested in permanent conquests. However, the corresponding tax burden led to growing resentment among the population and also among
Emperor Constans II. In addition, there may have been a wave of flight or emigration out of fear of another Arab attack. The real reason for the exarchate's 15-year respite was not due to the tribute payments, but to
internal Islamic disputes over the office of caliph. With a failed invasion of Sicily and a minor raid on Byzacena in the 650s, it was clear that the Arabs had not forgotten the West. Under Caliph
Mu'awiya I and his general ʿUqba ibn Nafiʿ, major attacks were resumed in 661, albeit initially only as raids. Around 668, Arabs attacked the island of
Djerba and the city of
Gigthi on the mainland, among other things. These events revealed the Byzantine emperor's inability to organize an effective defense for Africa. The subsequent assassination of
Constans II triggered 669 multi-year uprisings in Sicily, which not only prevented the intervention of further Byzantine troops in Africa, but even bound troops from Africa, which made it impossible to counter the new Arab invasion at an early stage. ʿUqba ibn Nafiʿ took advantage of this situation and launched the actual attack in 669. In the meantime, he set up an advanced army camp, laying the foundation for later
Kairouan, thus made it possible for the Arab armies to remain there all year round. While Byzantine troops kept sight of fortresses north of Kairouan, they sat idle, except relatively well-defended coastal cities. At the same time, due to the (same?) Armistice, it was determined that demarcation line was set along the Zeugitana-Byzacena line, thus Byzacena would be ceded to the Arabs, meanwhile, the Arabs would retreat from the region of
Zeugitana (composed of Carthage and its surrounding areas, i.e. Roman/Byzantine Africa in the narrowest sense). However, neither this nor
Fitnas prevented the Arabs from invading Numidia from 679, the region that had given Africa strategic depth and recruitment potential, so must therefore have been a thorn in the side of the general ʿUqba in particular. In the Lamasba area (today Mérouana),
Lambaesis and Thamugadi he won Pyrrhic victories in 682, which did not prevent him from his advance to the Atlantic. The Exarch was able to achieve a considerable defensive success in 683 when ʿUqba ibn Nafiʿ lost the
Battle of Vescera on the way back from the
Atlantic against the Berber tribes under their king
Kusaila, Byzantine troops and allied units and died in the process. The victors were even able to (re)take Kairouan.
Fall of the Exarchate of Carthage The defeated Arabs retreated to Egypt without their fallen general, giving the Exarchate and the Berbers some respite. But between 686 and 688 Arab armies defeated the Berber ruler Kusaila near Kairouan and, after his tribal alliance broke up, resumed their attacks against the Exarchate. This had been weakened by previous conflicts and had made insufficient use of the recovery phase. The military activities of the Arabs first required a renewed conquest of Barka, but before 688 it was again taken by sea-based Byzantine troops. In the first half of the 690s, the attacks on Carthage and its environs resumed, but were hampered by the Berber leader
Kāhina, who only lost battle and life at
Taharqa in the Aures range in 701. The assertion that the exarchate also received reinforcements from the Visigoths, whose king also feared an attack by the Arabs, is not proven. In 697/98 the Arab general
Hassan ibn al-Nu'man conquered Carthage for the first time with 40,000 men and was defeated by Kāhina. On the news of the conquest of Carthage, Emperor
Leontios dispatched the Byzantine fleet under the later Emperor
Tiberius III The fleet recaptured Carthage in the same year and fought the Arab fleet with varying success, but then went to Crete to pick up reinforcements. As a result, the Arab besiegers – who had initially retreated to Cyrenaica after their double defeat – succeeded in taking and destroying the city in cooperation with their fleet. Individual Byzantine towns and fortresses on the coast further west were probably only gradually conquered after the victory over Kāhina, such as
Vaga. In addition, according to Arab sources, Clupea (today
Kelibia) near
Cape Bon was the last city in Byzantine hands. The remote
Septem withstood an Arab siege by
Mūsā ibn Nusair in 706, but is said to have fallen to the Arabs at the latest when the Byzantine governor
Julian defected, who is said to have supported their attack on the Visigothic kingdom in 711. However, it is uncertain whether this was actually the case and whether Julian was a historical person at all. == Evaluation ==