The article consists of two parts. The first, published here, critically examines the transfer of Hellenistic- Jewish elements into the Christian liturgy, during the first 500 years of Christianity. It examines the term “national folksong” and its applicability in the instance of the musical tradition of the old synagogue; and the attitude of Western music historians to the question of Jewish influence on early Church music. The article deals with the possible approaches to the problem from a theological and musicological perspective. A second part of the article (which is not published here) proposes to deal with five ancient centers where Jews, Romans and Syrians lived together in a cultural and economic symbiosis. This research is meant to enable us to find a methodology which would lead us to those individuals who were active transferring the Jewish musical practice to the Christian Church.