now it was plainly to be seen that the death of the Emperor would fan into new life old passions — which in fact actually occurred. During the next few years the idea of any strong advance against the Saracens could not be entertained. Thus the citadel of Babylon capitulated in April 641. Therewith the eastern Delta and Upper Egypt lay in the hands of 'Amr. He thereupon crossed the Nile and, following the western branch of the river, advanced slowly towards Alexandria, capturing on his way the episcopal see of Nikiou, which capitulated on 13 May. Treachery and fear smoothed the way for him, but nevertheless he appears to have met with quite energetic opposition near Alexandria. He was, it is true, able to obtain possession temporarily of the vicinity of the town, but for the time being there could be no idea of subduing the great, strong Alexandria. As to the slow extension of the Muslim power in the remainder of Egypt we are not very well informed.
In the confusion following on the death of Heraclius the war party, represented as regards Egypt by the Augustalis Theodorus, appears to have gained the supremacy in Constantinople; then however, probably at the instigation of the Empress Martina, who was weary of the perpetual wars with the Saracens, Cyrus was again despatched to Egypt to arrange a capitulation with 'Amr under the most favourable conditions. Cyrus returned to Alexandria (14 Sept. 641) and his further policy is not quite clear. In any case, contrary to his former actions, he was most compliant to the Copts, and it is not improbable that he aimed at an Egyptian primacy under Arabian suzerainty. In the autumn, without the knowledge of the Alexandrians, he concluded the definite treaty with 'Amr, in accordance with which the city was to be evacuated by the Greeks not later than 17 Sept. 642, but for a stipulated tribute the residents were guaranteed their personal safety and the safety of their property, together with full freedom in the exercise of their religion. The Patriarch ran some risk of being lynched when this contract first became known, but he then appears to have convinced the people of its expediency. The Greeks quitted the town and it was actually given over to the Saracens at the appointed date. Cyrus did not live to see this, for he died previously (21 March 642). The capital of Egypt having fallen, 'Amr desired also to cover his flank; he therefore undertook in the following winter 642-643 an expedition to the Pentapolis and occupied Barka without striking a blow.
Alexandria was however no more selected as the seat of the new government than Ctesiphon had previously been chosen for this purpose. The policy of the Caliph was to isolate the Arabian element in the foreign land, and the Saracens therefore built for themselves a city of their own, near to the ancient Babylon, on the eastern bank of the Nile, in a similar way to their procedure at Kūfa and Baṣra; their camp was called by the Greeks "φόσσατον" i.e. "the camp," which name was transmuted in the Arabian idiom into "Fūsṭāṭ" (a tent). The list of
