What economic and political factors contributed to the centralization of land?

The Russian state, like many others, at the beginning of its development underwent feudal fragmentation. This slowed down the development of the country for several centuries. In the 14th century, tendencies towards centralization of the state began to appear. This was influenced by the external threat in the person of the Golden Horde. Also, within Russia, the preconditions for unification began to develop. The fragmentation of the principalities complicated trade and gave rise to disputes. The population could not carry out trade due to high customs duties on the border of the Russian principalities.