This battle became one of the greatest tragedies in our history. The flower of the Russian squads perished in this battle. This massacre is considered the prologue of the Tatar-Mongol yoke. On May 31, 1223, on the Kalka River, the Russian army was completely defeated by the Mongols - Rus' paid dearly for princely strife, lack of coordination of actions and the absence of a unified command. “And the slaughter was fierce and evil because of our sins. And all the Russian princes were defeated, as had never happened since the beginning of the Russian land... - the chronicle reports. “So for our sins, God took our minds away, and countless people died...” The story for the first time allows us to see the massacre from the inside, through the eyes of ordinary warriors who, before their princes, realized that individually the Russian principalities were doomed, and that only together, together, back to back.