Chagatai Khan (alternative spellings Chagata, Chugta, Chagta, Djagatai) was the second son of Genghis Khan. He inherited most of what are now the five Central Asian states and Northern Iran after the death of his father which he ruled until his death in 1241. He was also appoined by Genghis Khan to oversee the execution of the Yassa. The Empire late came to be known as the Chagatai Khanate part of the Mongol Empire.

He is also the person whom the Chagatai Turks generally and the Chughtais of South Asia claim descent.

Chughtai

This is a Family name/clan in South Asia (India, Pakistan, Afghanistan and the associated diaspora) that claims descent from Chagatai Khan, as thus status as a Chagatai Turk. The names of (especially) male members of the clan often carry the prefix Mirza and the suffix Beg, and are thus usually of the form Mirza <given name> Beg. The Mughal Emperors of India claimed to be of the same lineage. Babur consciously made a decision to drop the Mirza from his name. The names of minor, and some times even major, princes of the dynasty continued to carry the prefix and/or the suffix. The nomenclature is common today. For example, Mirza Aslam Beg was a recent Chief of Army Staff in Pakistan. Modern variations include the use of Beg or even Mirza as a family name. The family name Chughtai is also used. See also Bey.