Where did cannabis come from?

Cannabis came to the Middle East between 2000 B.C. and 1400 B.C., and it was probably used there by the Scythians, a nomadic Indo-European group…Germanic tribes brought the drug into Germany, and marijuana went from there to Britain during the 5th century with the Anglo-Saxon invasions. Over the next centuries, cannabis migrated to various regions of the world, traveling through Africa, reaching South America in the 19th century and being carried north afterwards, eventually reaching North America.

http://www.livescience.com/48337-marijuana-history-how-cannabis-travelled-world.html