Evidence for the earliest securely dated hominin presence in Europe comes from 1.4 million-year-old stone tools from Korolevo, in western Ukraine. Settlement by modern humans in Ukraine and its vicinity dates back to 32,000 BC, with evidence of the Gravettian culture in the Crimean Mountains. By 4,500 BC, the Neolithic Cucuteni–Trypillia culture was flourishing in wide areas of modern Ukraine, including Trypillia and the entire Dnieper-Dniester region. Ukraine is a probable location for the first domestication of the horse. The Kurgan hypothesis places the Volga-Dnieper region of Ukraine and southern Russia as the linguistic homeland of the Proto-Indo-Europeans. Early Indo-European migrations from the Pontic steppes in the 3rd millennium BC spread Yamnaya Steppe pastoralist ancestry and Indo-European languages across large parts of Europe. During the Iron Age, the land was inhabited by Iranian-speaking Cimmerians, Scythians, and Sarmatians. Between 700 BC and 200 BC it was part of the Scythian kingdom.