Background In the
Vandalic War of 533, Byzantine forces under
Belisarius reconquered the
Maghreb along with
Corsica and Sardinia and the
Balearic Islands. Emperor Justinian I () organized the recovered territories as the
Praetorian prefecture of Africa, which included the
provinces of
Africa Proconsularis,
Byzacena,
Tripolitania,
Numidia,
Mauretania Caesariensis and
Mauretania Sitifensis, and was centered at Carthage. In the 550s, a Roman expedition succeeded in regaining parts of southern Spain, which were administered as the new province of
Spania. After the death of Justinian in 565, the Eastern Roman Empire came increasingly under attack on all fronts, and emperors often left the more remote provinces to themselves to cope as best they could for extended periods, although military officers, such as
Heraclius the Elder (Exarch 598–610), continued to rotate between the eastern provinces and Africa. By the 640s and 650s, Byzantium had lost its
province of Mesopotamia to the Muslims, who also extinguished the Byzantines' rival, the
Sassanian Empire (651). Constantinople thereby lost an important source of experienced officers seasoned by constant border warfare with the Persians. The
Heraclian dynasty (610-711) did continue to appoint some competent eastern officers to African posts, such as the Armenian Narseh, who commanded Tripoli, and John, the
dux of
Tigisis.
Walter Kaegi speculates that some Armenian officers might have asked to transfer back to the east to defend their homes as the Muslims advanced into Armenia, but the sources are silent. Yet the officers who continued to arrive from the east after the loss of Mesopotamia would have been more accustomed to defeats like the
Battle of Yarmouk (636) than the previously winning strategies used against the Sassanians, and new tactics and strategies developed slowly. Among the provincial changes, Tripolitania was detached from the province of Africa and placed under the province of Egypt, Mauretania Caesariensis and Mauretania Sitifensis were merged to form the new province of "Mauretania Prima", while Mauretania Tingitana, effectively reduced to the city of Septum (
Ceuta), was combined with the citadels of the Spanish coast (
Spania) and the
Balearic Islands to form "
Mauretania Secunda". The
Visigothic Kingdom was a continuous threat to the exarchate. The African exarch was in possession of Mauretania II, which was little more than a tiny outpost in southern Spain. The conflict continued until the final conquest of the last Spanish strongholds in c. 624 by the Visigoths. The Byzantines retained only the fort of Septum (modern
Ceuta), across the
Strait of Gibraltar. During the successful revolt of the exarch of Carthage,
Heraclius the Elder, and his namesake son
Heraclius in 608, the
Berbers comprised a large portion of the fleet that transported Heraclius to Constantinople. Due to religious and political ambitions, the Exarch
Gregory the Patrician (who was related by blood to the imperial family, through the emperor's cousin
Nicetas) declared himself independent of Constantinople in 647. At this time the influence and power of the exarchate was exemplified in the forces gathered by Gregory in the
battle of Sufetula also in that year where more than 100,000 men of Amazigh origin fought for Gregory.
Arab Muslim conquest In 647, the first Islamic expeditions began with an initiative from Egypt under the emir
Amr ibn al-As and his nephew
Uqba ibn Nafi. Sensing Roman weakness they conquered
Barca, in
Cyrenaica, then moved on to
Tripolitania, where they encountered resistance. Due to the unrest caused by theological disputes concerning
Monothelitism and
Monoenergism, the exarchate under
Gregory the Patrician distanced itself from the empire in open revolt. The flood of refugees from Egypt (especially
Melkites), Palestine, and Syria exacerbated religious tensions in Carthage and further raised the alarm to Gregory of the approaching Arab threat. Sensing that the more immediate danger came from the Muslim forces, Gregory gathered his allies and confronted the Muslims, but was defeated at the
Battle of Sufetula, the new capital of the exarchate, since Gregory had moved to the interior for a better defense against Roman attacks from the sea. Afterwards, the exarchate became a semi-client state under a new exarch called
Gennadius. Attempting to maintain tributary status with Constantinople and Damascus strained the resources of the exarchate and caused unrest amongst the population. The exarchate scored a major victory over the forces of
Uqba ibn Nafi at the
Battle of Vescera in 682, aided by the
Berber king,
Kusaila. This victory forced the Muslim forces to retreat to Egypt, giving the exarchate a decade's respite. However, the repeated confrontations took their toll on the dwindling and ever-divided resources of the exarchate. In 698, the Muslim commander
Hasan ibn al-Nu'man and a force of 40,000 men
crushed Carthage. Many of its defenders were Visigoths sent to defend the exarchate by
Wittiza, who also feared Muslim expansion. Many Visigoths fought to the death; in the ensuing battle Carthage was again reduced to rubble, as it had been centuries earlier by the Romans. The loss of the mainland African exarchate was an enormous blow to the Byzantine Empire in the Western Mediterranean, because Carthage and Egypt were Constantinople's main sources of manpower and grain. The Byzantines never recovered their territories in Africa. == Known and postulated Exarchs of Africa ==