The article deals with the biography of Ivan Shusherin, the author of the “Life” of Patriarch Nikon. Based on new archival data, it was established the previously unknown circumstances of Ivan Shusherin’s ten-year stay in exile in Novgorod and his own letters, written in extremely beautiful handwriting are discovered. Analysis of the text of the “Life” allowed the author to clarify the dating of the “Life” and the intent of this work – the most important source on the history of the Russian church in the second half of the 17th century.