Probably the most famous people with the title Khan were Genghis Khan, the Mongol, and his grandson Kublai Khan, founder of the Mongolian dynasty in China known as Yuan Dynasty.
This title was first used by Rouran. Maybe the Xianbei used it earlier. At that time it was pronounced as Khaghan. The gh sound weakened. As the result of its disappearance Khaghan is Khaan in Modern Mongolian.
The Secret History of the Mongols clearly distinguishes Khaghan and Khan. Only Genghis and his descendants are called Khaghan and other rulers are referred to as Khan.
The title of Khan was also used in the Seljuq Islamic dynasties of the near-east to designate a head of multiple tribes, clans, or nations, who was below an Atabeg in rank.
See also: Khong Tayiji, List of Mongol Khad
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