"A migration that is identified, however, is east-to-west: “a part of the Timber-grave tribes moved [from Uzbekistan or even the Amu Darya basin] to the North Caucasus because of the crisis; they had already begun appearing and settling in the Caucasus at an earlier time”. (p.454) [This must be the Scythian migration, which only added to the already existing Iranian presence near and beyond the Urals. Intermittently, groups of Iranians must have moved from Bactria to the Urals and even to Ukraine for more than a thousand years. (One of the later migrating tribes were apparently the Hrvat, now known as the Croats. Before migrating west and adopting the Slavic language of the Serbs, they belonged to the Harahvaita tribe in Afghanistan mentioned as tribute-payers to the Persian empire in an Achaemenid document.)]"