The accounts by Josephus and Philo show that the Essenes (Philo: Essaioi) led a strictly celibate but communal life − often compared by scholars to Buddhist and later Christian monastic living − although Josephus speaks also of another "rank of Essenes" that did get married (War 2.160-161). According to Josephus, they had customs and observances such as collective ownership (War 2.122; Ant. 18.20), elected a leader to attend to the interests of them all whose orders they obeyed (War 2.123, 134), were forbidden from swearing oaths (War 2.135) and sacrificing animals (Philo, §75), controlled their temper and served as channels of peace (War 2.135), carried weapons only as protection against robbers (War 2.125), had no slaves but served each other (Ant. 18.21) and, as a result of communal ownership, did not engage in trading (War 2.127). Both Josephus and Philo have lengthy accounts of their communal meetings, meals and religious celebrations. From what has been deduced, the food of the Essenes was not allowed to be altered (by being cooked, for instance); and they may have been strict vegetarians, eating mostly bread, wild roots and fruits.[citation needed] After a total of three years probation (War 2.137-138), newly joining members would take an oath that included the commitment to practise piety towards the Deity and righteousness towards humanity, to maintain a pure life-style, to abstain from criminal and immoral activities, to transmit their rules uncorrupted and to preserve the books of the Essenes and the names of the Angels (War 2.139-142). Their theology included belief in the immortality of the soul and that they would receive their souls back after death (War 2.153-158, Ant. 18.18). Part of their activities included purification by water rituals, which was supported by rainwater catchment and storage.
...
The Essenes are discussed in detail by Josephus and Philo. Many scholars believe that the community at Qumran that allegedly produced the Dead Sea Scrolls was an offshoot of the Essenes; however, this theory has been disputed by Norman Golb and other scholars. Some suggest that Jesus of Nazareth was an Essene, and that Christianity evolved from this sect of Judaism, with which it shared many ideas and symbols.
According to Martin A. Larson, the now misunderstood Essenes were Jewish Pythagoreans who lived as monks. As vegetarian celibates in self-reliant communities who shunned marriage and family, they preached a coming war with the Sons of Darkness. As the Sons of Light, this reflected a separate influence from Zoroastrianism via their parent ideology of Pythagoreanism. According to Larson, both the Essenes and Pythagoreans resembled thiasoi, or cult units of the Orphic mysteries. John the Baptist is widely regarded to be a prime example of an Essene who had left the communal life (see Ant. 18.116-119), and it is thought they aspired to emulate their own founding Teacher of Righteousness who was crucified.
Another issue is the relationship between the Essaioi and Philo's Therapeutae and Therapeutrides (see De Vita Contemplativa). It may be argued that he regarded the Therapeutae as a contemplative branch of the Essaioi who, he said, pursued an active life (Vita Cont. I.1).
One theory behind the formation of the Essenes suggested they were the remnants of the Temple priests whose duties were usurped by Jonathan Maccabaeus(no of priestly lineage), perhaps referring to him as the "man of lies" who replaced the Teacher of Righteousness.