After being freed from Mongol rule, Muscovy didn't have a large economy nor population and was surrounded by states of equal strength such as Novgorod.
Despite this, over the years they were able to somehow gain a much bigger population (with the population of Siberia being rather small so I guess it didn't contribute much to this statistic once colonised) and economy in order to finally establish the Russian Empire and become a major European power.
How did they achieve this?
And on a side note, why is the Russian population so big, despite being historically rather small, having 6 million in 1500 compared to then Castile's 7 million or France's 15 million?
First of all, thanks for the question. It’s not often that people are so deeply interested in someone’s story.
The Principality of Novgorod, the Principality of Vladimir-Suzdal, the Principality of Tver, the Principality of Moscow is the core of modern Russia, this is Russia. All their divisions are very arbitrary. Moscow for Russia, is like Prussia for Germany.
This piriod (from the 13th to the 15th century) in Russian history is called feudal fragmentation. This happened after the Mongols ravaged and destroyed the city of United Rus (Kiev). Another important point, in those days there was the so-called suzerainty of the great princes of Vladimir (Vladimir-Suzdal principality). The Principality of Vladimir is the heart of Russia, the most respected and one of the oldest principalities in Russia. The authority of the Vladimir princes was recognized by all other principalities and republics of old Russia. Despite the fact that in the 14th century, Russia was still divided, in 1380 the Battle of Kulikovo took place. The majority of the Russian northern lands took part in this battle. And although a difficult victory did not lead to the end of the Horde dependence, it nevertheless had great political and spiritual significance as a symbol of the unity of the Russian people around Moscow. The Moscow and Vladimir Principality officially united (1389). From now on, the Moscow princes bore the title: Grand Duke of Moscow and Vladimir. Thus emphasizing that they are the main ones in Russia. From that moment, the Moscow princes began to "collect" Russian lands into a single state. In 1547, the Russian Kingdom was proclaimed: the Grand Duke of Moscow, Ivan IV, was crowned Tsar.
A brief summary: why Moscow principality? Because Dmitry Donskoy bequeathed the Principality of Vladimir to his son Vasily the first (Prince of Moscow). And as you hopefully remembered, the Principality of Vladimir was the main thing in Russia, and not Moscow. And also because it was Moscow, under its command, that gathered troops against the Mongols
By the time of liberation from the Mongol yoke, the Principality of Moscow was by no means a weak state, as you say. This actually was the strongest principality of all other Russian principalities. And also the richest, due to the unification with the Principality of Vladimir.
Novogorodskaya republic can be said to be a democracy with a republican form of government. They were located to the north, and not so often fought with the Tatars and Mongols. The main enemies of the New Novgorod Republic were the Swedes, who can not even remotely compare with the Mongol and Tatar army.
Muscovites also fought with the Tatars and also with the Mongols. These are the strongest armies of that period on the Eurasian continent. Contrary to the opinion of “some” experts, you cannot conquer one sixth of the land without a strong army.
Now about the issue of population. I’m not sure where the data indicates that in the 16th century, the population of Russia amounted to 6 million people. Russia is a huge country, and even the 16th century was such. I do not even remotely imagine how people in Russia could be counted in the 16th century. I suspect that the real population was higher.
"the backwater of Europe"
Well, depending on what is considered the backwater of Europe. Novogorodskaya, Pskov Republic were one of the first in Europe to have a republican form of government. With the republican form of government were also Switzerland, Venice, San Marino, Hamburg, Bremen, Dubrovnik Republic. From this point of view, the rest of Europe can be considered a backwater. (Except for the above republics)
Serfdom was introduced in Russia during the reign of Ivan the Terrible, and the peak fell at the time of the highest dawn of the Russian Empire. So the old Russia is by no means a backwater; Russia became a political backwater during the time of the empire. Also, I'm not sure how you compare the economies of the old states. And why do you think that Russia had a weak economy.
Russia was actively engaged in trade in fur, amber, honey, wax and other valuable goods. As well as jewelry. works of Russian jewelers Archaeologists find in Poland, the Czech Republic, Germany and the Baltic countries.
To summarize: Based on your incorrect assumptions, you draw incorrect conclusions.
History says otherwise:
a) The Principality of Moscow was not weak. b) The Mokov Principality definitely had money, otherwise there would have been no opportunity to unite the rest of Russia under its authority.
c) 16th century demographic statistics are not credible.