For centuries, linguists have believed that most European languages have so many similarities that they must have originated from a mother language, which is referred to as "Proto-Indo-European." Decades of work in linguistics have confirmed the existence of this language. But how did this language spread? The Lithuanian anthropologist Marija Gimbutas proposed her Kurgan Hypothesis, and argued that Old Europe was an egalitarian, peaceful, and artistic civilization that was conquered by a patriarchal, hierarchal, and warlike culture.