Kurgan hypothesis
The Kurgan hypothesis (also known as the Kurgan theory, Kurgan model, or steppe theory) is the most widely accepted proposal to identify the Proto-Indo-European homeland from which the Indo-European languages spread out throughout Europe and parts of Asia. It postulates that the people of a Kurgan culture in the Pontic steppe north of the Black Sea were the most likely speakers of the Proto-Indo-European language (PIE).