The history of Russian Freemasonry is naturally divided into three periods, which can be designated as the XVIII, XIX and XX centuries. For all the validity of such periodization, the designations themselves are sufficiently conditional. If for the 18th century the stages of the development of Freemasonry, highlighted in the monograph by G.V. Vernadsky "Russian Freemasonry in the reign of Catherine II" (the revised and expanded edition of which amounted to the first issue of the series "Russian Freemasonry. Materials and research"), then for the subsequent history of Freemasonry the chronological framework is "blurred." Let's explain what we mean.