Monastic life, which development has been significantly contributed by St. Gregory the Great, has an important place in the history of Europe. This paper attempts to go back to the period of monasticism in the Late Antiquity, of which there are numerous testimonies in the epistles of St. Gregory the Great. Based on Registrum epistularum, the paper presents the practice of admitting to the monas­teries candidates from different social backgrounds. Simultaneously, it discusses the evolution of the imperial law, from the reign of Constantine to the end of the sixth century, by concerning restrictions on the admission to the monasteries ari­sing from the fact of belonging to the specific state (obnoxii): decurions, tax col­lectors, colonate, slaves assigned to the land. The paper highlights the concern of Pope Gregory I for those who join the monasteries as well as draw attention to the motives, which guided the emperors to make laws concerning the admission to the monasteries and the Gregory’s attitude towards the secular law. The paper also draws attention to the efforts of the pope aiming at promoting the monastic life as the highest form of Christian life.