FTA; The rules governing religiously mixed families crystallised fairly early, at least on the Muslim side. The Quran allows Muslim men to marry up to four women, including ‘People of the Book’, that is, Jews and Christians. Muslim women, however, were not permitted to marry non-Muslim men and, judging from the historical evidence, this prohibition seems to have stuck. Underlying the injunction was the understanding that marriage was a form of female enslavement: if a woman was bound to her husband as a slave is to her master, she could not be subordinate to an infidel.
In the modern Middle East, intermarriage has become uncommon. One reason for this is the long-term success of Islamisation, such that there are simply fewer Jews and Christians around to marry. Another reason is that those Jewish and Christian communities that do exist today have survived partly by living in homogeneous environments without Muslims, or by establishing communal norms that strongly penalize marrying out. In contrast to todays world, where the frontiers between communities can be sealed, the medieval Middle East was a world of surprisingly porous borders, especially when it came to the bedroom.