Vilhelm Thomsen. 1912 / Wikimedia Commons

Monument to Kül Tigin with an Old Turkic inscription. Orkhon Valley, Mongolia. 8th century / Vezirtonyukuk / Wikimedia Common

Marble Statue of Bilge Qaghan. 8th century / National Museum of Mongolia, Ulaanbaatar / Wikimedia Commons

Emperor Xuanzong (Li Longji) of the Tang Dynasty. Portrait by an unknown Ming-dynasty artist / Wikimedia Commons

Emperor Wu of Han (r. 141–87 BCE) with co-regent Jin Midi, who was of Xiongnu origin. Relief from the Wu Liang Shrine, Jiaxiang, Shandong Province. 2nd century CE / Pictures from History / Getty Images

Mongol Siege of Zhongdu. Miniature from Rashid al-Din’s Jami' al-Tawarikh. Circa 1300 / Getty Images

Ilkhan Öljaitü Receiving Ambassadors from the Yuan Empire. Miniature from Hafiz-i Abru’s Majma al-Tawarikh. 15th century / Wikimedia Commons

Batu Khan on the Throne. Miniature from Rashid al-Din’s Jami' al-Tawarikh. Early 14th century / Wikimedia Commons

Letter from Ablai Khan to the Chinese Emperor. 1760 / Wikimedia Commons

Kazakh camps near Urumqi, Xinjiang, 1956. Tom Hutchins / Getty Images