Gregory the Patrician Gregory the Patrician ( , , died 647 ) was a Byzantine Exarch of Africa ( modern Tunisia and eastern Algeria ) . A relative of the ruling Heraclian dynasty , Gregory was fiercely pro - Chalcedonian and led a rebellion in 646 against Emperor Constans II over the latter ' s support for Monothelism . Soon after declaring himself emperor , he faced an Arab invasion in 647 . He confronted the invaders but was decisively defeated and killed at Sufetula . Africa returned to imperial allegiance after his death and the Arabs ' withdrawal , but the foundations of Byzantine rule there had been fatally undermined . Biography . Gregory the Patrician was related by blood to Emperor Heraclius ( r . 610 – 641 ) and his son Constans II ( r . 641 – 668 ) , and was possibly the son of Heraclius ' cousin Niketas . Gregory is first attested as Exarch of Africa ( " " patrikios " of Africa " in Theophanes ) in July 645 , but may have been appointed already under Heraclius . The Exarchate at this time was in internal turmoil due to the conflict between the mainly Orthodox Chalcedonian population and the supporters of Monotheletism , an attempt at compromise between Chalcedonianism and Monophysitism devised and promoted by Heraclius in 638 . In Africa , the latter was mostly advocated by refugees from Egypt . In an effort to lessen the tensions , in July 645 Gregory hosted a theological dispute in his capital Carthage between the Chalcedonian Maximus the Confessor and the Monothelite former Patriarch of Constantinople , Pyrrhus . Gregory helped to bring about a reconciliation between the two , and Pyrrhus re - embraced the Chalcedonian position . Over the next few months , several local synod s in Africa proceeded to condemn Monotheletism as heresy . In 646 , Gregory launched a rebellion against Constans . The obvious reason was the latter ' s support for Monotheletism , but it undoubtedly was also a reaction to the Muslim conquest of Egypt , and the threat it presented to Byzantine Africa . Given the failure of the imperial government in Constantinople to stop the Muslim advance , it was , in the words of Charles Diehl , " a great temptation for the powerful governor of Africa to secede from the feeble and remote empire that seemed incapable of defending its subjects " . Doctrinal differences , as well as the long - established autonomy of the African exarchate , reinforced this tendency . The Arab chronicler al - Tabari on the other hand claims that Gregory ' s revolt was provoked by a levy of 300 pounds of gold demanded by Constans . Arab sources claim that after he was proclaimed emperor he minted coins with his own effigy , but none have so far been found . It seems that both Maximus the Confessor and Pope Theodore I encouraged or at least supported Gregory in this venture . Thus the Pope supposedly sent an envoy to convey a dream by Maximus , according to which two rival choirs of angels shouted " Victory to Constantine [ Constans ] " Augustus " " and " Victory to Gregory " Augustus " " , with the former gradually falling silent and the latter winning out . The revolt seems to have found broad support among the populace as well , not only among the Romanized Africans , but also among the Berbers of the interior . In 642 – 643 , the Arabs had seized Cyrenaica and the eastern half of Tripolitania , along with Tripoli . It was only an order from Caliph Umar ( r . 634 – 644 ) that halted their westward expansion . In 647 , however , Umar ' s successor Uthman ordered Abdallah ibn Sa ' ad to invade the Exarchate with 20 , 000 men . The Muslims invaded western Tripolitania and advanced up to the northern boundary of the Byzantine province of Byzacena . Gregory confronted the Arabs on their return at Sufetula , but was defeated and killed . Agapius of Hierapolis and some Syriac sources claim that he survived the defeat and fled to Constantinople , where he was reconciled with Constans , but most modern scholars accept the Arab chroniclers ' account of his death in battle . The Arab accounts also claim that the Muslims captured Gregory ' s daughter , who had fought at her father ' s side . She was carried along back to Egypt as part of the booty , but she fell from her camel on the march and was killed . After Gregory ' s death , the Arabs sacked Sufetula and raided across the Exarchate , while the Byzantines withdrew to their fortresses . Unable to storm the Byzantine fortifications , and satisfied with the huge amounts of plunder they had made , the Arabs agreed to depart in exchange for the payment of a heavy tribute in gold . Despite the fact that the Arab raid was not followed up for some time , and the restoration of ties with Constantinople , Byzantine rule over Africa was shaken to its roots by Gregory ' s rebellion and the Arab victory . The Berber tribes in particular shook off their allegiance to the Empire , and most of southern Tunisia seems to have slipped outside the control of Carthage . Thus the Battle of Sufetula marked " the end , more or less near , but inevitable , of Byzantine domination in Africa " ( Diehl ) .