Answer:
Russian Orthodox Church.
Step-by-step explanation:
The Russian Orthodox Church is the largest of the Orthodox Churches. It developed after the East-West Schism, in the early 1000s, when the Orthodox Church and the Catholic Church emerged as two separate entities.
The schism was the result of a long period of development in which the eastern and western parts of the church had slipped apart. As long as this manifested itself primarily in external things - as in the liturgy - they could stick together, but as dogmatic differences also developed, the relationship became increasingly tense. This was due to the Pope's desires and demands to be the leader of the churches.
Then, in the 1400s, within the Orthodox Church there were various differentiations between the different aspects, within which the Russian Church separated from the rest, adapting Christian beliefs to the Russian idiosyncrasy itself.