The beginning of contradictions on socio-economic issues between the Church and the state dates back to 1503. During the 16th–18th centuries, the secular authorities improved the tools for controlling monastic property. A turning point in relations between the state and the Church in the socio-economic sphere occurred at the beginning of the 18th century. The historiography does not show the origins and prehistory of Peter I’s Church reform. The article presents a comparative historical analysis of the social and economic aspects of the transformation on the example of two dioceses of Northern Russia – Vologda-Belozersk and Ustiug-Tot’ma. The authors believe that the Church reform began not after the death of Patriarch Adrian in 1700, but in the 1690s. The realization that the Church had significant resources came to Peter I, apparently, during trips to the White Sea. The experience of describing the Northern dioceses in 1701 was extended to the whole country. The successful initial stage of the Church reform in 1696-1703, its important socio-economic component-all this, we believe, played a role in the subsequent administrative and legal reform of the Church, when it was organically incorporated into the apparatus of the absolutist state in Russia.