Among the earliest evidence of Cannabis cultivation comes from sites on the Western Steppe associated with tthe Yamnaya culture (3300–2600 BCE). Recent studies indicate the Yamnaya are also the strongest candidates for the Proto-Indo-Europeans. This supports the “Kurgan hypothesis” of Marijia Gimbutas.
Here’s an authoritative talk on the Indo-Europeans by renowned archaeologist, Colin Renfrew.
The photograph on the homepage shows a sculptural reconstruction of the face of a Yamnaya man.