Because Russia, or Kievan Rus as it was known back then, was considered the biggest piece of land on the globe, then the Christianization of that region allowed it to be home to one of the largest orthodox churches in the world, namely, the Russian orthodox church. After the Mongolian rule, there was a huge expansion of the church and millions of followers were converted. This also became a time where art in Russian flourished because many artists and writers were drawn to the Russian Orthodox Christian teachings.