Therapeutae

The Therapeutae were a religious sect which existed in Alexandria and other parts of the ancient Greek world.
The primary source concerning the Therapeutae is the "De vita contemplativa" ("The Contemplative Life"), traditionally ascribed to the Jewish philosopher Philo of Alexandria (c. 20 BCE – 50 CE). The author appears to have been personally acquainted with them. The author describes the Therapeutae as "philosophers" (cf. I.2) and mentions a group that lived on a low hill by the Lake Mareotis close to Alexandria in circumstances resembling lavrite life (cf. III.22). They were "the best" of a kind given to "perfect goodness" that "exists in many places in the inhabited world" (cf. III.21). The author was unsure of the origin of the name and derives the name Therapeutae/Therapeutides from Greek θεραπεύω in the sense of "cure" or "worship" (cf. I.2).
Philo's description of the doctrines and practices of the Therapeutae leaves great ambiguity about what religion they are associated with. Analysis by religious scholar Ullrich R. Kleinhempel indicates that the most likely religion the Therapeutae practiced was Buddhism. 
The word "Therapeutae" may also have been adapted from the Indian Pali word for traditional Buddhists, Theravada.
Name.
The term "Therapeutae" (plural) is Latin, from Philo's Greek plural "Therapeutai" (Θεραπευταί). The term therapeutes means one who is attendant to the gods although the term, and the related adjective "therapeutikos" carry in later texts the meaning of attending to heal, or treating in a spiritual or medical sense. The Greek feminine plural "Therapeutrides" (Θεραπευτρίδες) is sometimes encountered for their female members. The term "therapeutae" may occur in relation to followers of Asclepius at Pergamon, and "therapeutai" may also occur in relation to worshippers of Sarapis in inscriptions, such as on Delos.
De vita contemplativa account.
Philo described the Therapeutae in "De vita contemplativa" ("On the contemplative life"), written in the first century CE. The origins of the Therapeutae were unclear, and Philo was even unsure about the etymology of their name, which he explained as meaning either physicians of souls or servants of God. The opening phrases of his essay establish that it followed one that has been lost, on the active life. Philo was employing the familiar polarity in Hellenic philosophy between the active and the contemplative life, exemplifying the active life by the Essenes, another severely ascetic sect, and the contemplative life by the desert-dwelling Therapeutae.
According to "De Vita Contemplativa", the Therapeutae were widely distributed in the Ancient world, among the Greeks and beyond in the non-Greek world of the "barbarians", with one of their major gathering points being in Alexandria, in the area of the Lake Mareotis:
Teachings and lifestyle.
Temperance and simplicity.
They lived chastely with utter simplicity; they "first of all laid down temperance as a sort of foundation for the soul to rest upon, proceed to build up other virtues on this foundation" (Philo). They renounced property and followed severe discipline:
Six days per week of solitude, meeting on seventh day, with teaching and hymns.
They were dedicated to the contemplative life, and their activities for six days of the week consisted of ascetic practices, fasting, solitary prayers and the study of the scriptures in their isolated cells, each with its separate holy sanctuary, and enclosed courtyard:
On the seventh day the Therapeutae met in a meeting house, the men on one side of an open partition, the women modestly on the other, to hear discourses. Once in seven weeks they meet for a night-long vigil after a banquet where they served one another, for "they are not waited on by slaves, because they deem any possession of servants whatever to be contrary to nature. For she has begotten all men alike free" ("De Vita Contemplativa", para.70) and sing antiphonal hymns until dawn.
Testament of Job.
The pseudepigraphic "Testament of Job" is seen as possibly a Therapeutae text.
Early Christian interpretations.
The 3rd-century Christian writer Eusebius of Caesarea (c. 263–339), in his "Ecclesiastical History", identified Philo's Therapeutae as the first Christian monks, identifying their renunciation of property, chastity, fasting, and solitary lives with the cenobitic ideal of the Christian monks.
The 4th-century Christian heresiologist Epiphanius of Salamis (c. 315–403), bishop of Salamis in Cyprus, author of the "Panarion," or "Medicine Chest against Heresies", misidentified Philo's Therapeuate as "Jessaens" and considered them a Christian group.
The 5th-century Christian writer Pseudo-Dionysius, following Philo, interprets that "Some people gave to the ascetics the name 'Therapeutae' or servants while some others gave them the name monks". Pseudo-Dionysius interprets Philo's group as a highly organized Christian ascetic order, and the meaning of the name "Therapeutae" as "servants".
Relation to Buddhism.
Authors have pointed out similarities between the Therapeutae and early Buddhist monasticism, a tradition earlier by several centuries. As described in the 1st century CE "Periplus of the Erythraean Sea" text, Egypt had intense trade and cultural contacts with India during the period which, combined with Indian evidence of Buddhist missionary activity to the Mediterranean around 250 BCE (the Edicts of Ashoka), has led to the hypothesis that Therapeutae might have been a Buddhist sect, descendants of Ashoka's emissaries to the West. Linguist Zacharias P. Thundy suggests that the word "Therapeutae" is only a Hellenistic corruption of "Theravada", the Indian Pali word for traditional Buddhists.