Mamai (Mongolian Cyrillic: Мамай, Tatar: Мамай, Mamay; 1325?–1380/1381) was a powerful military commander of the Golden Horde. Contrary to popular misconception, he was not a khan (king), but a warlord and a kingmaker for several khans, and dominated parts or all of the Golden Horde for a period of almost two decades in the 1360s and 1370s. Although he was unable to stabilize central authority during a period of civil war, Mamai remained a remarkable and persistent leader for decades, while others came and went in rapid succession.
Unlike the khans of the so-called Golden Horde, Mamai was not a descendant of Genghis Khan and his son Jochi, but belonged to the powerful Mongol Kiyat clan, which claimed descent from Mugetu Kiyan (Mūngdū Qayān), an older brother of Genghis Khan's father Yesugei Baghatur. While they served the rulers of the Golden Horde from at least Batu Khan, the Kiyats may have risen in importance after the fall of the rival khan Nogai in 1299. Abandoning Nogai in favor of the legitimate khan, Toqta, Aq-Buqa Kiyat enjoyed the favor of the khan and his successor, and served as one of the chief emirs. Another Kiyat, Isatai, was entrusted with governing the former ulus of Orda in the eastern part of the Golden Horde, by Öz Beg Khan. Isatai's son Jir-Qutluq and the latter's son Tingiz-Buqa enjoyed the same position under the next khans, Jani Beg and Berdi Beg. Specific information about Mamai's immediate origins is very limited, but his father is named as Alash Beg (possibly Ali Beg), probably the son of Tuluq-Timur Kiyat, and therefore possibly the brother of the aforementioned Isatai. At least part of the clan may have been ensconced in the Crimea, perhaps since the early 14th century, before several Kiyats appeared as governor on the eastern periphery of the Golden Horde. The date of Mamai's birth can be estimated only generally, to somewhere in the mid-to-late 1320s. At birth, he appears to have received the Muslim name Muḥammad, sometimes paired with the nickname Kičik ("little"), perhaps due to his short stature. Whether "Mamai" is a variation of that name or an additional, "folk" name, remains unclear.