The authors explore the sources of a chapter from the «Lalitavistara», a Mahayana sutra narrating the life of Buddha. The analysed part of the sutra presents Buddhist concept of an ideal ruler and briefly describes the main kingdoms of ancient India. The question discussed is whether the text can be used as a historical source reflecting political reality. To answer this question, one has to trace the history of the text and to reveal the historical material used in it. For this purpose the authors explore Chinese translations of the «Lalitavistara» reflecting earlier versions of the sutra. They also publish Russian translation of all the texts concerned, because there has been neither any Russian translation of the «Lalitavistara» nor any translations of its Chinese versions in European languages.