Demographic history of Russia
This article presents the demographic history of Russia covering the period of Kievan Rus, its successor states, the Mongol domination and the unified Tsardom of Russia. See Demographics of Russia for a more detailed overview of the current and 20th century demographics. Kievan Rus, Mongol invasion and vassalage. Population. Kievan Rus was a loose federation of East Slavic and Finnic peoples in Europe from the late 9th to the mid-13th century. The population of Kievan Rus is estimated to have been between 4.5 million and 8 million, however in the absence of historical sources these estimates  are based on the assumed population density. The great majority of the population was rural and lived in small villages with no more than ten households, except for some exceptionally fertile areas such as Zalesye. The urban populations were estimated by Tikhomirov based on the data from the chronicles: militia size, fortified area, number of churches, epidemic victims and burned houses. Kiev had tens of thousands of inhabitants, the population of Novgorod numbered 10-15 thousand in the beginning of 11th century and 20-30 thousand 200 years later. Smolensk, Polotsk (currently a city in Belarus), Vladimir and Chernigov (now  Volodymyr-Volynskyi and Chernihiv in Ukraine) were comparable in size to Novgorod, while the great majority of the other cities had no more than 1000 citizens. Subsequent archeological research produced similar numbers for the biggest cities: up to 35 thousand in Novgorod and up to 50 thousand in Kiev. 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 Edigu's 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 Muscovite Civil War. Internal migrations. The lands of Rostov-Suzdal Principality were settled by Slavs in this period, with the native Finno-Permic speakers being gradually assimilated. In the North the territories between Onega and Ladoga lakes and along Svir, Northern Dvina and Vyatka rivers attracted Novgorodian settlers. The Mongol invasion triggered an internal migration from less secure Southern lands to the forested regions of Moscow, Tver and Upper Volga. Social stratification. The population of Kievan Rus consisted of nobility (boyars), free and partially free  peasants (smerd, "zakup", "ryadovich") and kholops whose status was similar to that of slaves. Tsardom of Russia. Population. The first reliable data on the number of households dates to the late 15th century, when Ivan III carried out several censuses of the newly incorporated Novgorod land. As these censuses counted adult heads of households the total population estimates of Novgorod land vary between 500 and 800 thousand. By the end of 15th century most of East Slav lands formerly belonging to Kievan Rus were divided between the Grand Duchy of Moscow and the Grand Duchy of Lithuania. The population of  the former was estimated to be around 5.8 million in 1500, growing to 9-10 million by 1550. Vodarsky estimates the population in mid-16th century to be 6.5 million, growing to 7 million by the end of it. The contemporary population of the Grand Duchy of Lithuania numbered 3.6 million, with Ruthenians constituting the majority (see Demographic history of Poland). As the population of Muscovy was growing the size of the average peasant allotment declined (though there were significant regional variations) and the wages declined as well while the grain prices soared. The Livonian War led to the increase of  tax burden on the peasants and when the crops failed in 1567 and 1568 a famine ensued, followed by a plague of 1570-1571. In the best-documented Novgorod land some regions lost between 40 and 60% to famine, decease and emigration. The relatively calm period of 1584-1600 was followed by the Time of Troubles when a few consecutive crop failures led to a famine and a collapse of the Russian state, foreign interventions and widespread destruction. The population size only reached the 1600 level fifty years later. According to the census of 1678 there were 950,000 households in  Russia. The estimates for the total population range between 10.5 and 11.5 million depending on the assumptions of the average number of individuals in a household and of the percentage of population that avoided the census. As the census was used to determine poll taxes due, both peasants and landlords had the incentive to minimise the number of counted households. They could conceal them, combine several households into one or report peasants as household servants (дворовые люди) who were not taxed. The biggest cities in the 16th century were Moscow (41,500 households), Pskov (6,000) and Novgorod (5,500), while in the  17th century Yaroslavl became the second biggest city after Moscow. Internal migrations. The settlement of southern borderlands continued during this period. The former Wild Fields became safer as the new defence lines and fortresses were founded and its rich soils attracted settlers from the central Russia. The conquest of Siberia started in late 16th century and within one hundred years most of Siberia belonged to Russia. At that time there were 40 thousand Russian peasants in Siberia and the settlement gathered pace in the beginning of 18th century. Social stratification. Peasants constituted 90% of households in 1678, with 3% of  townsfolk (посадские люди) and 7% of untaxed classes (service class people and clergy) according to the census of 1678. Serfs living on the lands belonging to the nobility, the church or the royal family accounted for the majority or the peasants, with the remainder consisting of personally free peasants and yasak-paying non-Russians. Almost half of all serfs owned by nobles belonged to 535 richest landowners while the other 14,500 landowners owned the rest. The odnodvortsy were part of the service class people and thus did not pay taxes even though they normally did not own any serfs (hence  the name, literally one-householders). Ethnic composition. The conquest of the Kazan and Astrakhan Khanate brought a large Muslim Tatar population alongside Chuvash, Mari and Mordvin people into Russia.