Three Manifestations
Debt, First 5000 Years, Graeber
For most of the Middle Ages, the economic nerve center of the world economy and the source of its most dramatic financial innovations was neither China nor India, but the West, which, from the perspective of the rest of the world, meant the world of Islam. During most of this period, Christendom, lodged in the declining empire of Byzantium and the obscure semi-barbarous principalities of Europe, was largely insignificant.
Since people who live in Western Europe have so long been in the habit of thinking of Islam as the very definition of “the East,” it’s easy to forget that, from the perspective of any other great tradition, the difference between Christianity and Islam is almost negligible. One need only pick up a book on, say, Medieval Islamic philosophy to discover disputes between the Baghdad Aristoteleans and the neo-Pythagoreans in Basra, or Persian Neo-Platonists-essentially, scholars doing the same work of trying to square the revealed religion tradition beginning with Abraham and Moses with the categories of Greek philosophy, and doing so in a larger context of mercantile capitalism, universalistic missionary religion, scientific rationalism, poetic celebrations of romantic love, and periodic waves of fascination with mystical wisdom from the East.
From a world-historical perspective, it seems much more sensible to see Judaism, Christianity, and Islam as three different manifestations of the same great Western intellectual tradition, which for most of human history has centered on Mesopotamia and the Levant, extending into Europe as far as Greece and into Africa as far as Egypt, and sometimes farther west across the Mediterranean or down the Nile.