When the role of Kiev was overtaken by new centres, Novgorod, Vladimir and Galich, in the fist half of the XIII century, Tatars came to Rus. They were totally unfamiliar and unexpected. A chronicler wrote: "The pagans came and nobody knows who they are and where they come from and what their language is and what their religion is."
The motherland of Tatars was Mongolia. Dispersed tribes were united by khan Temuchin, who took the title of Genghis Khan (The Great Khan). In 1213, he started his conquests by occupying the northern China, then he moved westwards and reached the Caspian sea and Armenia, bringing destruction and terror everywhere. The vanguard of Tatars went from the southern shores of the Caspian sea through Caucasus mountains into the steppes to north from Black sea, where they met the Polovtsians. Polovtsians asked knyazes of southern Rus for assistance. Knyazes of Kiev, Chernigov and Galich (all named Mstislav) agreed to help, thinking that if Tatars subjugate Polovtsians they will become even stronger. For a number of times, the Tatars sent ambassadors to the Russian army saying that they are not in war with Rus, that their only enemies are Polovtsians, but the knyazes kept on going till they met Tatars on river Kalka (1223). Knyazes were defeated. Tatars tortured and killed the captured knyazes and warriors, than turned backwards and disappeared.
Some years later, in 1227, Genghis Khan died and split his conquered lands between his sons, but giving the supreme power to one of them, Ugede. Ugede sent his nephew Batu, son of Juchi, to conquer the western lands. With a horde of Tatars, Batu crossed river Ural (old name Yayik). On Volga, he defeated the Volga Bulgars and sacked their capital the Great Bulgar. Having crossed Volga, in the end of 1237 he came to the duchy of Ryazan, ruled by Olgoviches, the descendants of knyaz Oleg (see chapter 18). Batu Khan demanded for tribute — "one tenth of everything", but he was refused. Ryazan asked other Russian knyazes for help, but nobody came and they had to withstand the Tatars alone. Tatars overcame, burnt and sacked the whole province, kiled or enslaved the population and moved northwards. They devastated Moscow and entered the duchy of Rostov and Suzdal. The grand prince of Vladimir, Yuri Vsevolodovich, left his capital Vladimir and went to the north-west to collect an army (see February 7 in Russian history). Tatars seized Vladimir, killed the family of the knyaz, burnt the city and devastated the remaining towns of the duchy. They met knyaz Yuri on river Sit' (a tributary of Mologa, which is in its own turn a tributary of Volga). On March 4, 1238, Russians were defeated again and Tatars moved to Tver and Torzhok and entered the lands of Novgorod. They turned back in around 150 kilometres from Novgorod and headed to the steppes. On the road, they had to spend a lot of time during the siege of the city Kozelsk, which fell after an unusually long and brave defence. So, in 1237-1238, Batu Khan conquered the north-western Rus.
Later, Batu Khan began the conquest of the southern Rus from his camps on the lower Don and Volga. In 1239 he sacked Pereyaslavl and Chernigov and in 1240 he attacked Kiev. In the end of 1240 Tatars took Kiev after a cruel battle. From Kiev, they moved to Volyn' and Galich, captured them, crossed the Carpathian mountains and entered Hungary and Poland. After a brave rebuff he met in Czechia, they turned backwards and founded a new province of the Tatar empire, the Golden Horde, in the steppes. A new city Sarai, founded on the lower Volga, became the capital of the Golden Horde.