The Siege of Kiev by the Mongols took place between November 28 and December 6, 1240, and resulted in a Mongol victory. It was a heavy moral and military blow to Halych-Volhynia and allowed Batu Khan to proceed westward into Europe.
In 1237, the Mongols began their invasion of Rus by conquering the northern principalities of Ryazan and Vladimir-Suzdal. In 1239, they advanced against southern Rus, capturing the cities of Pereyaslav and Chernihiv.
The next year, the Mongol general Batu Khan reached Kiev. At the time, the city was ruled by the principality of Halych-Volhynia. The chief commander in Kiev was Voivode Dmytro, while Danylo of Halych was in Hungary at that time, seeking a military union to prevent invasion. The number of defenders inside the city was only about 1,000.