If horseback riding really did began at the turn of the IV mil. B.C. before the dispersal of Proto-Indo-European, it did not leave traces in the vocabulary of the later dialects. . . . Thus it cannot be proven that this type of ancient . . . horseback riding had originally been connected with Indo-Europeans.

— Vyacheslav Ivanov Ivanov (1999)

Notes from Wikiquote

Ivanov, Vyacheslav. 1999. "Comparative Notes on Hurro-Urartian, Northern Caucasian and Indo-European." UCLA Indo-European Studies 1:147-264 (233).23