 Complete the following phrase:  The Mongol invasion in the 13th century devastated most of Kievan Rus, with only the North-West Novgorod, Pskov, Smolensk escaping the widespread destruction. Out of 74 major cities, 49 were destroyed and many of them were abandoned or became villages. Two thirds of settlements in the Moscow region disappeared. The recovery started in the beginning of the 14th century, with new lands entering cultivation, new settlements appearing and monumental construction growing quickly. In Novgorod Land, which was less fertile than the North-East and could support lower population density, there are signs of over-population starting from the 1360s: epidemics, high food prices, famines, peasants falling into arrears and losing their lands to nobles and monasteries. The North-East was hit by Edigus invasion and by pestilence in the beginning of 15th century which led the author of the chronicle to remark that few people remained in all the Russian land и мало людий во всей Русской земле остася. This was followed by the 