<P> Khan is a title for a sovereign or a military ruler, used by Mongolians living to the north of China . Khan has equivalent meanings such as "commander", "leader", or "ruler", "king" and "chief". As of 2015 khans exist in South Asia, Middle East, Central Asia, Eastern Europe and Turkey . The female alternatives are Khatun and Khanum . These titles or names are sometimes written as Han, Kan, Hakan, Hanum, or Hatun (in Turkey) and as "xan", "xanım" (in Azerbaijan), and medieval Turkic tribes . </P> <P> "Khan" also occurs as a title in the Xianbei confederation for their chief between 283 and 289 . The Rourans may have been the first people who used the titles khagan and khan for their emperors . However, Alexander Vovin (2007) believes that the term qaγan originated among the Yeniseian - speaking Xiongnu people, and then diffused across language families . Subsequently, the Göktürks adopted the title and brought it to the rest of Asia . In the middle of the sixth century the Iranians knew of a "Kagan--King of the Turks". </P> <P> Various Mongolic and Turkic peoples from Central Asia gave the title new prominence after period of the Mongol Empire (1206--1368) in the Old World and later brought the title "khan" into Northern Asia, where locals later adopted it . Khagan is rendered as Khan of Khans . It was the title of Chinese Emperor Emperor Taizong of Tang (Heavenly Khagan, reigned 626 to 649), and also the title of Genghis Khan and of the persons selected to rule the Mongol Empire . For instance Möngke Khan (reigned 1251 - 1259) and Ogedei Khan (reigned 1229 - 1241) would be "Khagans" but not Chagatai Khan, who was not proclaimed ruler of the Mongol Empire by the kurultai . </P> <P> Originally khans headed only relatively minor tribal entities, generally in or near the vast Mongolian and North Chinese steppe, the scene of an almost endless procession of nomadic people riding out into the history of the neighbouring sedentary regions . Some managed to establish principalities of some importance for a while, as their military might repeatedly proved a serious threat to such empires as China and kingdoms in Central Asia . </P>

Who were the khans and where did they come from