How did the Mongols conquer Rus' and why did Moscow rise under them?

The Mongols struck in winter, against a state that was already falling apart, and took its cities one by one. A first Mongol force had won a victory at the Battle of the Kalka River in 1223, and then retreated, having learned what they came to learn. When the real invasion came, a Hungarian friar who had travelled to the eastern border reported that the Mongol army was waiting for winter, so that it could cross the frozen rivers and swamps. Rivers that would have protected the towns in summer became roads.

The towns fell fast. Ryazan fell after three days. Vladimir, the capital of Vladimir-Suzdal, was besieged on 4 February 1238, and three days later it was taken and burnt to the ground. A chronicler wrote that unknown nations had arrived, and that no one knew where they came from or what religion they practised. Not every place fell: the small town of Kozelsk, led by a boy-prince, resisted for seven weeks, and Novgorod was spared by deciding to surrender in advance. In December 1240 the Mongols stormed Kyiv, an event generally held to mark the end of the state of Kievan Rus'.

What came next was rule through payments. Principalities that avoided conquest were forced to pay tribute and accept Mongol supremacy, sometimes as outright vassals of the Golden Horde. Most historians say the invasion only accelerated a break-up of Kievan Rus' that had begun before.

And one winner emerged. After the prince of Tver rose up in 1327, Ivan I of Moscow joined the Mongols in crushing it. He gained the title of Grand Prince from the Mongols, and the Russian Orthodox Church moved its headquarters to Moscow. Mongol domination of Russian lands lasted until 1480.