Stanislav of Znojmo (died 1414), a professor of the Prague Theological Faculty, first a teacher and friend to Jan Hus, but then his decided opponent, wrote a comprehensive treatise, probably around 1403, entitled De vero et falso. The subject of my article is an analysis of the content of this work. In it, Stanislav deals with the question of the truth of a proposition and the problem of its truth-maker. The question of the truth-maker falls into the area of metaphysics, and so the author speaks of metaphysical truth. In so far as metaphysical truth is concerned, Stanislav of Znojmo defends a decidedly realist standpoint, judging that categorematic expressions are not alone in having real counterparts in the world, but syncategorematic expressions (for example, statement conjunctions, words expressing negations and so on) also have such counterparts. Stanislav’s treatise, in its overall orientation, belongs to propositionalism, a trend in logical thought widespread at the end of the Middle Ages. Although the author of the treatise De vero et falso does not cite contemporary authors, he shows a knowledge of some exponents of propositional logic (namely Gregory of Rimini, for example). His main inspiration, however, is undoubtedly the work of John Wyclif.