No single, coherent chapter on the societies of modern Syria (Arabic, al-Shām) and Sicily (Arabic, Ṣiqilliyah) could or would be written today: Sicily is a Western Christian state; Syria an Arab and Islamic one. But for most of the Middle Ages, there was no such clarity about these societies’ dispositions. War and regime change plagued both territories. Political power passed back and forth among Persian, Aramaic, Greek, and Latin conquerors. These rulers included partisans of the popes of Rome, the patriarchs of Constantinople, the Sunnī caliphs of Baghdad, and the Shīʿī imams of Cairo. As a result of these changes in regime, as well as ongoing immigration and emigration, medieval Syria and Sicily came to host ethnolinguistic and confessional communities whose diversity reflected that of their wider Mediterranean world. Among these populations, substantial Syrian and Sicilian Jewish communities survived and often thrived throughout the Middle Ages.