The latest evidence of the invasion and the existence of an early Byzantine fortification confirm that the fortified city in which the Arabs established the administrative centre of the island, as the Arab sources mention, was Herakleion. We can imagine that the invaders, moving gradually from south to north and conquering fortresses one after the other, as the sources describe, would have approached the fortified city from the south, cutting off its supply from the mainland and driving its inhabitants to despair, until they surrendered around 828 AD.

Herakleion became the capital of the Emirate of Crete, a muslim border state similar to Sicily, with an autonomous administration and its own currency, which nevertheless acknowledged the rule of the caliphs of Baghdad.  The Andalusian followers of Abū Hafs, who had been forced to leave the Iberian Peninsula after their revolt against the harsh treatment of the Emir of Andalusia al-Hakam, were mainly of urban origin. They did not seem to be interested in agriculture and stockbreeding, the main occupation of the local population, except perhaps from a fiscal point of view. Most of them settled in the major urban centres, especially Herakleion, which they named Rabd el-Khandaq, the fortress with the moat, or Chandax for the Byzantines. There, according to Byzantine sources, they built beautiful houses surrounded by gardens with fruit trees and fountains, they became skilled craftsmen and developed an intense trade in goods and crafts with Egypt, Andalusia and other Islamic countries. Intellectuals existed as well. They probably coexisted peacefully with the local population, as there are no reports of massacres or violent Islamisation. The list of loot compiled by Nicephorus Phocas after the city’s recovery reflects its wealth: precious carpets, golden weapons and objects of fine art.

The emirs of Crete tried to extend their dominance in the Aegean with continuous attacks, during which some islands were occupied and forced to pay taxes, while others were deserted. The ultimate target of these attacks appears to be Constantinople itself and the control of the Aegean trade routes. Thus, for the Byzantines, the reconquest of Crete and the dispersion of the Emirate became a matter of survival.