The Invention of the Jewish People
, by Israeli historian Shlomo Sand, is a fascinating read. Chapter 3 cites a great deal of evidence that Judaism in the Persian, Hellenistic, and Roman eras was already a universalizing, missionary monotheism, long before Christianity. It converted large masses of gentiles and sometimes entire kingdoms. Sand argues that both Christian and Zionist cultures have for various reasons tended to obscure this historical reality.
And many of the people of the land became Jews; for the fear of the Jews fell upon them (Esther 8:17).
"This is the only mention in the Bible of conversion to Judaism, and this statement about mass conversions--not at the End of Days but in the present--indicates the strengthening confidence of the young Jewish monotheism. It may also hint at the source of the great increase in the number of Jewish believers in that period."
"A 1965 doctoral thesis by Uriel Rapaport--unfortunately not published--deviated from the usual [Israeli] historiographic discourse and sought, without success, to draw researchers' attention to the widespread wave of conversions. Unlike all the ethnonationalist historians, Rapaport did not hesitate to conclude his brilliant thesis with this statement: 'Given its great scale [peaking at ~7-8% of population under Roman empire], the expansion of Judaism in the ancient world cannot be accounted for by natural increase, by migration from the homeland, or any other explanation that does not include outsiders joining it.
As he saw it, the reason for the great Jewish increase was mass conversion. This process was driven by a policy of proselytizing and dynamic religious propaganda, which achieved decisive results amid the weakening of the pagan worldview. In this, Rapaport joined a (non-Jewish) historiographic tradition that included the great scholars of ancient history--Renan, Wellhausen, Meyer, Schurer--and asserted, to use the sharp words of Theodor Mommsen, that 'ancient Judaism was not exlcusive at all; it was, rather, as keen to propagate itself as Christianity and Islam would be in the future.' (pp. 153-54).
"In almost all of the narratives produced by the proto-Zionist and even Zionist historians, conversion is mentioned as one reason for the vast presence of Jewish believers throughout the ancient world before the fall of the Second Temple. But this decisive factor was sidelined, while the more dramatic players of Jewish history dominated the field: expulsion, displacement, emigration, and natural increase. These gave a more appropriate ethnic quality to the "dispersion of the Jewish people. ...It is generally assumed that Judaism has never been a missionizing religion, and if some proselytes joined it, they were accepted by the Jewish people with extreme reluctance."
"The period between Ezra in the fifth century BCE and the revolt of the Maccabees in the second was a kind of dark age in the history of the Jews. ...What we do know is that, while the abundant biblical texts during this Persian period promoted the tribal principle of an exclusive "sacred seed," other authors wrote works that ran counter to the hegemonic discourse, and some of those works entered the canon. The Second Isaiah, Ruth, Jonah, and the apocryphal Judith all call for Judaism to accept gentiles, and even for the whole world to adopt the "religion of Moses." (pp. 150-51)