Judaism arrived at the same practice by an entirely different road, and the difference is instructive. Scripture does not forbid a man more than one wife and reports it of the patriarchs and the kings without censure, so the change could not be made by exegesis. It was made by enactment. A ban attributed to Rabbenu Gershom of Mainz, around the year 1000, prohibited polygamy for the communities under his authority, and it was accepted across Ashkenaz. Sephardi and Mizrahi communities living in the Islamic world, where plural marriage was lawful, did not adopt it, and the permission stood among them into the modern period.
The state of Israel closed the gap by legislation rather than by ruling, criminalising bigamy and requiring rabbinic courts to work within that, with transitional arrangements for immigrants from countries where the practice was legal. The chief rabbinate has generally treated the Ashkenazi ban as effectively universal in practice.
Set against the rest of the map, monogamy is a rule in some traditions and an assumption in others. Islamic law permits up to four wives on conditions and many Muslim-majority states now restrict or regulate it. Hindu law in India prohibits it by statute for most citizens. Many African, South Asian and Indigenous traditions carried it as custom rather than as doctrine. The atlas records monogamy as a settled Christian teaching and a modern legal norm across much of the world rather than as a universal religious rule.