In different periods of history, the title of “khan” has had various orthographic forms such as “khaghan” or “gha'an” with meanings close to each other, however. In the 11th and 12th centuries BCE, the word “khaghan” had been in common use in China. In the 5th to 7th centuries CE, Turkic tribes also used this word to refer to their rulers and kings. In the Islamic period, this word was first used to refer to the rulers of the Ilak-Khaniyyeh dynasty (382-607 A.H.). Nevertheless, the word was also in use during the Seljuq, Khwarizmshahid, Mongol, Afsharid, and Zand periods, and even the contemporary era in Iran.
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