Hemp is Cannabis Sativa, but of a strain bred over a couple thousand years for fiber as opposed to psychoactive constituents. Cannabis Indica is the "heavy-hitter" that originated in Afghanistan and various Indo-European and Semitic peoples spread it around the Central Asian / Caucasus region as well as India, North Africa and the Middle East. Cannabis Sativa has strains that are psychoactive and those were predominantly found in Asia and Eurasia. Indo-Europeans brought it into Europe during various migration periods. Early Germanic and Norse tribes used it quite a bit, which they probably learned from steppe nomads during the Volkerwanderung.