The author of this article atempts to bring back the term “reformers before the Reformation” used in historical scholarship in the 19th century and related to the understanding of “evangelical heresy”. The author believes that the realization of Sacred Scripture as the supreme authority in all maters of faith, understood as the mystical focus of the soul, is the source of Reformation ideas in general and the philosophy of John Wycliffe in particular. The author identifies the peculiarities of Wycliffe’s approach to exegesis and the translation of Sacred Scripture, analyzes his logical and metaphysical foundations, and demonstrates how the hypostatization of general names (universals) leads the teacher of the Gospel to necessitarianism (the teaching that existence is an absolute truth, which limits Divine omnipotence). This allows us to explain the peculiarity of Wycliffe as an ideologue of the Lollards and a forerunner of the Reformation in the 16th century through the firmness of his intellectual traditionalism and his urge not simply for renewal, but also for the purification of Christian doctrine.