When one’s picture of the past is based on a single set of texts, the encounter with a new source of information is likely to provoke much reflection and revision, as the data from the different sets of evidence are compared to each other. It was the special blessing of those who wrote the Jewish history of antiquity during the sixteenth century, after knowledge for many previous generations had been based on Rabbinic texts and Iosippon (the Byzantine adaptation in Hebrew of a Latin version of Josephus), to discover all that could be derived from Greco-Roman evidence and from the writings of ancient Jews preserved in Greek and Latin. The Qumran texts are the gift to scholars of our generation, provoking a new round of critical reflection on what can be learned from the Rabbis. Much which we thought we knew with certainty will have to be reconsidered, while some of the information preserved by the Rabbis which we rejected as blatantly unhistorical will be seen in a new light, as we take up the challenge of comparing and integrating the new information with the old.
Albert I. Baumgarten, “Rabbinic Literature as a Source for the History of Jewish Sectarianism in the Second Temple”, Dead Sea Discoveries, Vol. 2, No. 1 (April 1995), 57.