The collapse of the Cuman realm after the Mongol invasions

Scholars tend to underline the Cuman vitality; Golden cited the famous statement of al-'Umarī, according to which the Mongols later mixed
and intermarried with the conquered Kıpçaks and became like their subjects; I myself discovered Cumans in the service of Daniil of Galicia and Vladimir-in-Volyn’ in 1245, which means that that particular group of Kıpçaks survived the Mongol invasion and now lived in the vicinity of the Mongol dominions. Yet these optimistic statements should not conceal the collapse of the Kıpçak world. The Cuman aristocracy was slain; their sacred stone figures were oſten purposefully destroyed; and while the Kıpçaks gave birth to, or at least enriched, many Turkic nations (the Tatars, Crimean Tatars, Kazakhs, Kirgizs, Uzbeks, the Turkic people of the North Caucasus and the Altai Mountains), the very name ‘Kıpçak’ was eventually replaced by ‘Tatar’ for the entire territory covered by the Golden Horde. The Codex Cumanicus, our chief source of Cuman, reflects the changing name of the language. In the first two parts of the Codex, which were written on paper made during the first half of the fourteenth century (the terminus ante quem of the work), the language is described as comanicum or chomanico. By contrast, the later parts of the Codex referred to the language as ‘Tatar’ (tatar til). Indeed, the very name ‘Kıpçak’ survived in the Armeno-Kıpçak documents composed in L’viv and Kamianets’ Podil’s’kyi in the sixteenth and seventeenth centuries. Ironically, we do not know the ethnic identity of the Armeno-Kıpçak people: as the acts were written in Armenian characters, and were, mainly, translations of Armenian sources, one may suggest that the speakers were either Armenians who had adopted the Kıpçak language, or Kıpçaks who had turned Armenian.

Korobeinikov D., "A broken mirror: the Kıpçak world in the thirteenth century," in Curta, F. – Kovalev, R. (eds), The Other Europe in the Middle Ages. Avars, Bulgars, Khazars, and Cumans (Leiden 2008), pp. 406-7.