The article presents the results of many years of research on the ethnosocial and political history of the Kazan Khanate, the culture of the ruling stratum and the taxable population of this medieval state. Historical sources indicate that in the Khanate, with the supremacy of Islam and the growth of its influence on all spheres of life in the country, there was complete religious and linguistic tolerance, which was associated with the traditions of the Khazar Khaganate, Volga-Kama Bolgaria, the Mongol Empire and the Golden Horde. It is also important to point out the rather wide polylingualism and multiculturalism of the population of the Kazan state. The necessity of polylingualism and multiculturalism in educational and communication space “in the era of post-literacy” noted by many modern scientists and teachers, it turns out, has long been successfully realized in different countries in the Middle Ages, for example, in the XV-XVI centuries in the Kazan Khanate.