After launching a spectacular campaign of conquest that, in just a few years, had brought Genghis Khan’s troops to militarily control a vast territory stretching from China to Persia, the Mongols arrived at the gates of Europe for the first time in 1222. That year, they crossed the Caucasus Mountains from the south, penetrating Georgia and the steppes north of the Black Sea, which were inhabited by the Cumans. Though this was merely a raid, and a numerically limited one at that, it was enough to prompt an alliance between the Cumans, led by Khan Kotjan, and several princes of the Rus'. This alliance led to the first military clashes, in which the Rus'-Cuman forces initially achieved some victories, only to suffer a crushing defeat at the hands of a small Mongol vanguard in the Battle of the Kalka River (1223). This first Mongol incursion at the doorstep of the Rus’ ended without further advances beyond the southern steppes, partly because, just a few years later, the Asian nomads had to deal with internal struggles over the succession of Genghis Khan, who died in 1227.  

The Mongols reappeared on the borders of the Rus’ more than a decade later, in 1237, this time under a new leader, Batu Khan, and with well-defined plans for conquest. It seems that the Eastern Slavic princes did not fully grasp the imminent danger, focusing more on their regional conflicts than on the broader threat. A prime example of this was the policy of Yuri II of Vladimir-Suzdal’ against the Volga Bulgars, which only served to weaken the southeastern defensive front, precisely where the Mongols struck.  

Batu's strategy for conquest typically began with sending envoys to demand submission and tribute from their enemies. If refused, they would launch a devastating military campaign. This was exactly what happened with the Rus’ princes, the majority of whom refused to yield. Thus began the first Mongol campaign against the Rus’: the first city to fall was Ryazan in December 1237, followed by Moscow and Vladimir between February and March of 1238. The Mongols occupied the entire Volga region but failed to advance as far as Novgorod, as the arrival of spring complicated their logistics, Mongol cavalry relied on frozen rivers for easier passage. The campaign resumed in 1239 with the conquests of Pereyaslavl and Chernihiv, culminating in December 1240 with the fall of Kyiv. At this point, the Mongol conquest of the Rus’ was effectively complete.