The region's written history begins with the region's conquest by the Achaemenid Empire of ancient Iran, as the region was divided between the satraps of Margiana, Chorasmia and Parthia. Later conquerors included Alexander the Great, the Parni, Ephthalites, Iranian Huns, Göktürks, Sarmatians, and Sassanid Iranians. During this early phase of history, the majority of Turkmenistan's inhabitants were either adherents of Zoroastrianism or Buddhism and the region was largely dominated by Iranian peoples. These incursions and epochs, though pivotal, did not shape the region's history as the invasions of two later invading groups: Arabs and the Oghuz Turks. The vast majority of inhabitants were converted to Hanifism, while the Oghuz brought the beginnings of the Turkic Turkmen language that came to dominate the area. The Turkic period was a time of cultural fusion as Islamic traditions brought by the Arabs merged with local Iranian cultures and then were further altered by Turkic invaders and rulers such as the Seljuks. Genghis Khan and Mongol invasions devastated the region during the late Middle Ages, but their hold upon the area was transitional as later Timur Leng and Uzbeks contested the land.