From Sicily: An Island at the Crossroads of History, by John Julius Norwich (Random House, 2015), Kindle pp. 58-59:
Sicily, like neighboring Calabria, became a haven for refugees from the iconoclast movement in the empire; but in the ninth it was shattered. The Arabs had waited long enough. They had by now occupied the entire length of the North African coast, and had already been harassing the island with sporadic raiding. Then in 827 they saw their chance of achieving permanent occupation. The local Byzantine Governor, Euphemius by name, had recently been dismissed from his post and recalled to Constantinople after an unseemly elopement with a local nun. His reply was to rise in revolt and proclaim himself Emperor, appealing to the Arabs for aid. They landed in strength, rapidly entrenched themselves, took little notice of Euphemius—who soon came to a violent end—and three years later stormed Palermo, making it their capital. Subsequent progress was slow. Messina fell in 843; Syracuse suffered a long and terrible siege, during which the defenders were finally reduced to cannibalism. The city surrendered only in 878. After this the Byzantines seem to have admitted defeat. A few isolated outposts in the eastern part of the island held out a little longer—the last, Rometta, even into the middle of the tenth century—but on that June day when the banner of the Prophet was raised over Syracuse, Sicily became, to all intents and purposes, a part of the Muslim world.
Once the wars of conquest were over and the country had settled again, life continued pleasantly enough for most of the Greek Christian communities. Although they had to endure a degree of discrimination as second-class citizens, they were normally allowed to keep their freedom, on payment of an annual tribute which many must have preferred to the heavy taxation and compulsory military service imposed by the Roman Empire. Meanwhile the Saracens displayed, as so often throughout their history, a degree of religious toleration which permitted the churches and monasteries and the long tradition of Hellenistic scholarship to flourish as much as ever they had done. In other ways too the island benefited from its conquerors. They brought with them a whole new system of agriculture, based on such innovations as terracing and siphon aqueducts for irrigation. They introduced cotton and papyrus, melon and pistachio, citrus and date palm and enough sugarcane to make possible, within a very few years, a substantial export trade. Under the Byzantines Sicily had never played an important part in European commerce, but with the Saracen conquest it soon became one of the major trading centers of the Mediterranean, with Christian, Muslim and Jewish merchants all thronging the bazaars of Palermo.
And yet, among the many blessings conferred upon Sicily by her Arab conquerors, that of stability was conspicuously absent. As the links of loyalty which bound the Emir of Palermo and his fellow chieftains to the North African caliphate grew ever more tenuous, the emirs themselves lost their cohesive force; they became increasingly divided against one another, and so the island found itself once again a battleground of warring factions. It was this steady political decline that was to bring the Greeks in strength back to Sicily—together with their Norman allies.
Far Outliers 