Wikipedia
Raskol
Raskol (, , meaning "split" or " schism") was the event of splitting of the Russian Orthodox Church into an official church and the Old Believers movement in the mid-17th century. It was triggered by the reforms of Patriarch Nikon in 1653, which aimed to establish uniformity between Greek and Russian church practices.
Usage examples of "raskol".
Not only Western Christianity has had to reckon with them: they have brothers today among the Mohammedan Sufi and in obscure Buddhist sects, and they were the chief preachers of the Russian Raskol, or Reformation.