The population of the region has been primarily Armenian for the majority of its known history. Prior to the appearance of nominally "Armenian" people in historical records, historians have hypothesized that the region must have been home to various ethnic groups who became homogenous when the Armenian language came to prominence. The population of the Armenian Highlands seem to have had a high level of regional genetic continuity for over 6,000 years. Recent studies have shown that the Armenian people are indigenous to the Armenian Highlands and form a distinct genetic isolate in the region. The region was also inhabited during Antiquity by minorities such as Assyrians, Georgians, Greeks, Jews, and Iranians. During the Middle Ages, Arabs and particularly Turkmens and Kurds settled in large numbers in the Armenian Highlands. The Christian population of the western half of the region was exterminated during the Armenian Genocide of 1915. Today, the eastern half is mainly inhabited by Armenians, Azerbaijanis and Georgians, while the western half is mainly inhabited by Kurds (including Yazidis), Turks, Azerbaijanis, Armenians (included crypto-Armenians and Hemshins) and Zazas.