Who are “lovers of God” or “zealots of piety”? How did they end up near Tsar Alexei Mikhailovich? What role did Hegumen Nikon play in this party and why did he become the Patriarch of All Rus' in 1652? What does Russia owe him and what does it have the right to condemn him for? Whose fault was it that the religious schism arose? And, finally, who and how, having corrected Nikon’s political mistakes, saved the Moscow state from great trouble, although he could not save it from the tragedy of church division? The author of the book offered to the reader tried to answer these and other questions, based on an analysis of the currently available documentary base in various publications and studies, with the use of archival materials, if necessary.