Taught the history of religion at the University College for Women in Petersburg, 1906-1918. Chairman of the Religious-Philosophical Society in Petersburg, a meeting place for the intelligentsia and the clergy, 1909. Appointed Procurator of the Holy Synod by the Provisional Government and after the abolition of this office, Minister for Religious Affairs, 1917.
Arrested in 1918 after the October Revolution. Emigrated 1919. Lived in Paris from 1920. Professor at the St. Sergius Theological Institute in Paris, 1925-1960.
An outstanding representative of the new religious intelligentsia of the 20th century. Historian of the church and religious thought.