The article examines the current hypotheses about time and place of translation of so-called Simple Prologue (hagiographic Synaxarium) in the Slavonic environment. Special attention is paid to the latest studies in the field. As additional arguments to answer the question are given the data on Russian and South Slavonic (mostly Bulgarian) commemorations in the early version of the Prologue. These data allowed to reject the existing hypotheses and to support the conclusion that the Simple Prologue was translated in the time of Samuil of Bulgaria in Archbishopric of Ohrid at the end of tenth – beginning of eleventh century. The translation was made very soon after the occurrence of Synaxarium in Byzantium and was due to the liturgical necessity.