Before I begin explaining anything about the History of name Khan you should know that Khan in its origin has nothing Islamic in it.
Khan in Turkic languages means “lord”, similar to Mongolian
Khan in ancient times was simply used as a singular word which had a massive masculinity to it, which made different people from different background adopt it.
The Title Khan in History was considered to be originated somewhat in central Asia.
Khan was made a famous surname by the massive Mongol Rulers . This title was also taken up by Turks who were also associated with the Mongol empire.
The title Khan became an International sensation when one of the most famous ruler in the history Timujin who adopted the name “Chengiz Khan” meaning “Universal King, he became leader of one of the largest empire in the history, from Asia to Europe, word about him reached in every part of the world.
The Mongols killed about 40 million Muslims in 13th century during their conquest of Central Asia and Middle East.
Chengis Khan became the “Great Khan” or Khakhan or Khaqan of the Mongols in 1206 after he unified the fragmented Mongol tribes into a unified entity.
Khan then simply was a word which defined the power.
Later in the Mongol Empire Bereke Khan became the first Mongol rulers to take up Islam as religion.
Mongols, Tatars and Turks fought together mostly in the mongol army this led to the some fusion of religions.
For Ex- Babur the Mughal conqueror of India descended from the Turkish Timur from his paternal side and directly from the family of Chagatai Khan, the son of Chengis Khan from his maternal line.
Till the middle of the sixth century, the word was still known to be used by these kings slowly the forces became so distributed and expansive that when invaders started attacking India the name Khan became so popular that it became an Integral part of Indo-Muslim culture.
This title wasn’t just confined to Indo-Muslim rule, soon people in east and west of India started using it as a title bestowed upon them by their rulers.
Pathans migrated to various regions of India from Pushtun speaking regions of Afghanistan and Pakistan and kept their family names and surnames which were usually Khan, soon anyone migrating from the afghan region were referred by Indians as Khan.
This is the full history of surname Khan
Khan today is one of the most famous Surname globally. Many famous personalities specially famous artists are khans and have inspired people with their beautiful work.