Therborn on the period between the fourth and eighth centuries (36): "The first wave of globalization was a transcontinental spread of religions, creating what we now, more than 1000 years later, call 'world religions.' In a remarkably short time, 400-500 years, all the heartlands of all the world religions were established, and still exist today. The boundaries of contemporary civilizations have been extended, contracted or blurred since then, but the cores remain the same. I think this period of historical diffusion is more interesting than the so-called 'axial age,' a notion developed by the German philosopher Karl Jaspers"
Interrestingly, "[i]n this period, Buddhism [...] lost for good its original home base in India," to be replaced by "the vast, polymorphous constellation known as Hinduism"