‘Jewish sectarianism in the Second Temple period’ contextualizes the Dead Sea Scrolls within the history of Second Temple Judaism and discusses the origins and history of the Qumran community of the Essenes. The period began under Persian rule, when Cyrus adopted a policy of religious tolerance. Alexander’s conquest of Judaea led to Hellenistic rule, until the Maccabaean revolt gained Jewish freedom. The Qumran–Essenes did not view Maccabaeans as legitimate rulers, so left the group before the Hasamonaean dynasty began. Judaism at this time comprised many sects. Some, such as the Qumran–Essenes, were introversionist and isolated, whereas others were reformist and remained in wider society.