4. Patrician, as Theophanes calls him, of the Byzantine province of Africa at the time of its first invasion by the Saracens. By the aid of the "Africans" (by which term we are probably to understand the Moors), Gregory revolted from the Byzantine empire, and made himself " tyrannus," or independent sovereign of the province. This was in A. D. 646, in the reign of Constans II. [CONSTANS II.] Perhaps his insurrection suggested or encouraged the purpose of invading the province ; for the next year (A. D. 647), the Mohammedan army advanced westward from Egypt, and Gregory was entirely defeated by them. We gather from Theophanes only the bare facts of Gregory's revolt and defeat; but Arab or Moorish writers afford various particulars of a very romantic and improbable character, which have been embodied in the work of Cardonne, and copied at length by Gibbon. (Theophan. Chronog. vol. i. p. 525, ed. Bonn; Cardonne, Histoire de de l'Afrique et de l'Espagne sous la Domination des Arabes, vol. i. p. 11, &c.; Gibbon, 100.51.)