The reasons for the allocation of Slavic tribes among the Indo-European peoples.

Reasons for allocation:
1) Formation of the ancient Slavic ethnic community;
2) The need for land for settlement.
The separation of the ancient Slavs from the Indo-European peoples occurred at the end of the 2nd millennium BC.
Ultimately, Slavic tribes settled in large areas in central and eastern Europe. So the first mention of the Slavs in these territories dates back to the 4th century AD. At the same time, the Great Migration of Peoples took place, which provoked the resettlement of the Slavs, the active phase of which took place in the 6th century.