This article offers a contextual study of the concept of terrenus in the treatises of Blessed Aurelius Augustine "On True Religion" and "On the Book of Genesis Literally". Based on the analysis of the use of the adjective "terrenus" in the above treatises, the author concludes that, although all the basic provisions of the concept have already been set out in the treatise "On True Religion", in the treatise "On the Book of Genesis Literally" they, appearing in a new context, clarify some provisions implicitly contained already at an early stage of the development of this concept. Thus, in the sociopolitical theory of St. Augustine, a number of key concepts and terms are highlighted, one of the most important is the noun "civitas", which has several semantic meanings — "commune", "community" or "city", and the corresponding definitions associated with it are Dei — "Divine", caelestis — "heavenly", or diaboli — "diabolical" and, of direct interest, terrena — "earthly".