The ethnical aspect and peculiarities of Mari culture had formed in the second half of first millenium A.D. The whole following history of Mari people is connected to Vetluzhsky-Vyatsky interstream area and adjacent part of Volga's right-bank lands. Mari ancient settlements on this territory and burial grounds located in these territories and studied by archeologists are the evidence of rich original culture which has been forming during the interaction process between Marians and kindred nations speaking other languages: Muroms, Meryans, Mordvians, Udmurts, as well as with representatives of Slavonic-languaged and Turki-languaged inhabitants. The relationship between Mari people with Slavonic Russian world started long ago, already in Kievan Russia. These contacts intensified in 1221 after the foundation of Nigny Novgorod. During the unification of Russian principalities around Moscow the part of northwestern and northern Mari that lived along Vetluga and middle stream of Vyatka became a part of Moscovian state. In XI-XV centuries Russians were moving to the east step by step, along rivers to Ural and further into Siberia.
Since Long ago Middle Volga lands and lower banks of Volga were ruled by the Golden Horde and later, after its disintegration, by Khazan and Astrakhan khanates. In second half of XV century and first half of XVI century Khazan khanate sent its forces against Russian lands more than 30 times. A real menace of the antirussian union under the aegis of Osmanian Empire appeared. After the accession of the Crimean dynasty of Girei in 1521 in Khazan Crimeans and Khazanians started joint raids to Russian lands began. The main aim of Russian eastern policy in XVI century became the protection of state against the intervention of Horde's successors. The military and political potential of Russia became so significant to that moment that even allowed solving the question cardinally: the Khazanian and Astrakhanian khanates were defeated. Russian success was also stipulated by the fact that Chuvashes, Marian highlanders, Mordvians and part of Tatarians took its part. In the end of 1546 year ambassadors of Marian highlanders asked the sovereign Ivan IV to "give them a favor and send a warrior host against Khazan". In June 1551 year after the negotiations of Marian ambassadors with the tsar the Marian lands situated on the right bank were taken as a part of Russian state.
And Lands beyond Volga, the meadow part of Marian Land, came under control of Russian tsar after the fall of Khazan in October 1552. Right away after meadow Marians and Udmurts sent their elders and sotniks to Ivan the Terrible wishing to take the Russian patriality and consenting to pay tribute to Russian tsar. On the 10th of October they swore to Ivan IV. Thus the process of Marian land becoming a part of Russian state was legally completed. The Middle Volga bank land becoming a part of Russian state became a stage event in history of our multinational fatherland. And for Mari people that meant not just a choice of historic path but much more: joining All-European and world civilization. Being a part of Russian state Mari people found themselves in highly developed feudal system. Land relationships didn't change after Mari became a part of Russia. People's rights for arable land, meadows, forests, hunting and wild-hive beekeeping lands were kept and confirmed by tsar's charters. The integration of Mari lands into Russian state continued up to the end of XVI century. On its territory were founded town - fortresses that lately became administrative centers of uyezds. In 1574 there was founded Kokshaysk, the first city in the land, Kosmodemyansk was found in 1583 and Tzarevokokshaysk was found in 1584. The colonization of Mari land's territory by Russians took place during so-called "free peasant colonization", which was typical for Russian state of XVIII-XIX centuries. Russian peasants migrated here from many places but mainly from northern uyezds of Vyatskaya province. The land mainly developed according to social-economical end political processes that took place in Russia at that time.