Siege of Kolomna
1236 CE.
Shown on the map at 55.083°, 38.783°.
The siege of Kolomna during December 1237–January 1238 was part of the Mongol invasion of Kievan Rus'. Following the Battle of Voronezh River in December 1237, Yuri II of Vladimir sent both of his sons with "all his men" and Voivode Yeremey to defend the fortress of Kolomna, which was on the border to the Wild Fields.
Text from the Wikipedia article Siege of Kolomna, licensed CC BY-SA 4.0.