A shramana (समण, Saman in Magadhi, Addhamagadhi, Shourseni, Mrahatti, pali and other Prakrit Languages, Sanskrit śramaṇa श्रमण) is a wandering monk in certain ascetic traditions of ancient India including Jainism, Buddhism, and Ājīvika religion (now extinct). Famous śramaṇa include religious leaders Mahavira and Gautama Buddha.
Traditionally, a śramaṇa is one who renounces the world and leads an ascetic life for the purpose of spiritual development and liberation. Typically śramaṇas assert that human beings are responsible for their own deeds and reap the fruits of those deeds, for good or ill. Liberation, therefore, may be achieved by anybody irrespective of caste, creed, color or culture (in contrast to certain historical caste-based traditions) providing the necessary effort is made. The cycle of rebirth, saṃsāra, to which every individual is subject, is viewed as the cause and substratum of misery. The goal of every person is to evolve a way to escape from the cycle of rebirth. Sramanic traditions dispense with the rites and rituals of formal religion as factors in emancipation, emphasizing instead the paramount importance of ascetic endeavor and personal conduct.
The Sanskrit word śramaṇa is derived from the Sanskrit verbal root śram "to exert effort, labor or to perform austerity". "Śramaṇa" thus means "one who strives" in Sanskrit.But the original word is Saman which means one who believes in Samata, i.e. equality.
One of the earliest uses of the word is in the Hindu text Taittiriya Aranyaka (2-7-1) with the meaning of 'performer of austerities'. A traditional Sanskrit definition is śramati tapasyatīti śramaṇaḥ ("a śramaṇa is he who exerts himself and performs religious austerities").
Buddhist commentaries associate the word's etymology with the quieting (samita) of evil (pāpa) as in the following phrase from the Dhammapada, verse 265: samitattā pāpānaŋ ʻsamaṇoʼ ti pavuccati ("someone who has pacified evil is called samaṇa").
Various forms of the word became known throughout Central and East Asia, largely through the spread of Buddhism in that area. According to a still disputed etymology, the word shaman, used by the Tungus people for their religious practitioners, may be borrowed from a local variant of the word śramaṇa.
Several śramaṇa movements are known to have existed before the 6th century BCE dating back to Indus valley civilization.
Samkhya and Yoga are two early and very important philosophies that follow the Sramana philosophy and which had their origins in the Indus Valley period of about 3000-2000 BCE. Yoga is probably the most important Sramana practice to date, which follows the Samkhya philosophy of liberating oneself from the grip of Prakriti (nature) through individual effort. Elaborate processes are outlined in Yoga to achieve individual liberation through breathing techniques (Pranayama), physical postures (Asanas) and meditations (Dhyana). Patanjali's Yoga sutra is one product (school) of this philosophy. Other Yogic schools and the Tantra traditions are also important derivatives and branches of the Sramana practices.
The movement later received a boost during the times of Mahavira and Buddha when Vedic ritualism had become the dominant tradition in certain parts of India. Śramaṇas adopted a path alternate to the Vedic rituals to achieve liberation, while renouncing household life. They typically engage in three types of activities: austerities, meditation, and associated theories (or views). As spiritual authorities, at times śramaṇa were at variance with traditional Brahmin authority, and they often recruited members from Brahmin communities themselves, such as Cānakya and Śāriputra.
Mahāvīra, the 24th Jina, and Gautama Buddha were leaders of their śramaṇa orders. According to Jain literature and the Buddhist Pali Canon, there were also some other śramaṇa leaders at that time. Thus, in the Mahāparinibbāna Sutta (DN 16), a śramaṇa named Subhadda mentions:
...those ascetics, samaṇa and Brahmins who have orders and followings, who are teachers, well-known and famous as founders of schools, and popularly regarded as saints, like Pūraṇa Kassapa, Makkhali Gosāla, Ajita Kesakambalī, Pakudha Kaccāyana, Sañjaya Belaṭṭhaputta and the Nigaṇṭha Nātaputta....
Nigaṇṭha Nātaputta (Pāli; Skt.: Nirgrantha Jñātaputra) refers to Mahāvīra. In regard to the above other teachers identified in the Pali Canon, Jain literature mentions Pūraṇa Kassapa, Makkhali Gosāla and Sañjaya Belaṭṭhaputta. (The Pali Canon is the only source for Ajita Kesakambalī and Pakudha Kaccāyana.)
Gautama Buddha regarded extreme austerities and self-mortification as useless or unnecessary in attaining enlightenment, recommending instead a "middle way" between the extremes of hedonism and self-mortification. Devadatta, a cousin of Gautama, caused a split in the Buddhist saṅgha by demanding more rigorous practices. Followers of Mahāvīra continued to practice fasting and other austerities.
The śramaṇa idea of wandering began to change early in Buddhism. The bhikṣu started living in monasteries (Pali, Skt. vihāra), at first during the rainy seasons, but eventually permanently. In medieval Jainism also, the tradition of wandering waned, but it was revived in the 19th century. Similar changes have regularly occurred in Buddhism.
Indian philosophy is a confluence of Śramaṇic (self-reliant) traditions, Bhakti traditions with idol worship and Vedic ritualistic nature worship. These co-exist and influence each other. Śramaṇas held a view of samsara as full of suffering (or dukkha). They practiced Ahimsa and rigorous ascetism. They believed in Karma and Moksa and viewed re-birth as undesirable.
Vedics, on the contrary believe in the efficacy of rituals and sacrifices, performed by a privileged group of people, who could improve their life by pleasing certain Gods. The Sramanic ideal of mendicancy and renunciation, that the worldly life is full of suffering and that emancipation requires abandoning desires and withdrawal into a solitary contemplative life, is in stark contrast with the Brahminical ideal of an active and ritually punctuated life. Traditional Vedic belief holds that a man is born with an obligation to study the Vedas, to procreate and rear male offspring and to perform sacrifices. Only in later life may he meditate on the mysteries of life. The idea of devoting one's whole life to mendicancy seems to disparage the whole process of Vedic social life and obligations. Because the Sramanas rejected the Vedas, the Vedics labelled their philosophy as "nastika darsana" (heterodox philosophy).
Beliefs and concepts of Śramaṇa philosophies:-
Denial of creator and omnipotent Gods
Rejection of the Vedas as revealed texts
Affirmation of Karma and rebirth, Samsara and transmigration of Soul, Later, these practices were accepted into Vedism.
Affirmation of the attainment of moksa through Ahimsa, renunciation and austerities
Denial of the efficacy of sacrifices and rituals for purification.
Rejection of the caste system
Ultimately, the sramana philosophical concepts like ahimsa, karma, re-incarnation, renunciation, samsara and moksa were accepted and incorporated by the brahmins in their beliefs and practices, eg. by abandoning the sacrifice of animals. According to Gavin Flood, concepts like karmas and reincarnation entered mainstream brahaminical thought from the sramana or the renounciant traditions. According to D. R. Bhandarkar, the Ahimsa dharma of the sramanas made an impression on the followers of Brahamanism and their law books and practices.
Following are the two main schools of Sramana Philosophy that have continued since ancient times in India:
Jainism derives its philosophy from the teachings and lives of the twenty-four Tirthankaras (ford-makers or enligtened teachers), of whom Mahavira was the last. Jain Acaryas - Umasvati (Umasvami), Kundakunda, Haribhadra, Yaśovijaya Gaṇi and others further developed and reorganized Jain philosophy in its present form. The distinguishing features of Jain philosophy are its belief in the independent existence of soul and matter, predominance of karma, the denial of a creative and omnipotent God, belief in an eternal and uncreated universe, a strong emphasis on non-violence, an accent on relativity and multiple facets of truth, and morality and ethics based on liberation of the soul. The Jain philosophy of Anekantavada and Syadvada, which posits that the truth or reality is perceived differently from different points of view, and that no single point of view is the complete truth, have made very important contributions to ancient Indian philosophy, especially in the areas of skepticism and relativity. 
Buddhist philosophy is a system of beliefs based on the teachings of Siddhartha Gautama, a Nepali prince later known as the Buddha. Buddhism is a non-theistic philosophy, one whose tenets are not especially concerned with the existence or nonexistence of a God or gods and which denies the existence of a creator god. The question of God is largely irrelevant in Theravada Buddhism, though most sects of Mahayana Buddhism, notably Tibetan Buddhism and most of East Asian Buddhism (in the Shurangama Mantra and Great Compassion Mantra) do regularly practice with a number of gods (as Dharmapalas and Wrathful Deities, Four Heavenly Kings, and Five Wisdom Kings) drawn from both the Mahayana Sutras and Buddhist Tantras sometimes combined with local indigenous belief systems. The Buddha criticized all concepts of metaphysical being and non-being. A major distinguishing feature of its philosophy is the rejection (anatman) of a permanent, self-existent soul (atman).
Usage of "Śramaṇa" in Jain texts
In Jainism the monks and ascetics are known as Śramaṇas , while the Jain laymen are called Sravakas. The religion or code of conduct of the monks is known as Śramaṇa Dharma. Jain canons like Ācāranga Sūtra and other later texts contain many references to Sramanas. One verse defines a good Sramana as:
Disregarding (all calamities) he lives together with clever monks, insensitive to pain and pleasure, not hurting the movable and immovable (beings), not killing, bearing all: so is described the great sage, a good Sramana.
The chapter on renunciation contains a Sramana vow of non-possession:
I shall become a Sramana who owns no house, no property, no sons, no cattle, who eats what others give him; I shall commit no sinful action; Master, I renounce to accept anything that has not been given.' Having taken such vows, (a mendicant) should not, on entering a village or free town, take himself, or induce others to take, or allow others to take, what has not been given.
Acaranga Sutra gives three names of Mahavira, the twenty fourth Tirthankara, one of which was 'Sramana' :
The Venerable ascetic Mahavira belonged to the Kasyapa gotra. His three names have thus been recorded by tradition: by his parents he was called Vardhamana, because he is devoid of love and hate; (he is called) Sramana (i.e. ascetic), because he sustains dreadful dangers and fears, the noble nakedness, and the miseries of the world; the name Venerable Ascetic Mahavira has been given to him by the gods.
Another Jain canon, Sūtrakrtanga describes the Sramana as an ascetic who has taken Mahavratas, the five great vows:
He is a Sramana for this reason that he is not hampered by any obstacles, that he is free from desires, (abstaining from) property, killing, telling lies, and sexual intercourse; (and from) wrath, pride, deceit, greed, love, and hate: thus giving up every passion that involves him in sin, (such as) killing of beings. (Such a man) deserves the name of a Sramana, who subdues (moreover) his senses, is well qualified (for his task), and abandons his body.
In a disputations with other heretical teachers, prince Ardraka, who became disciple to Mahavira, tells Makkhali Gosala the qualities of Sramanas:
He who (teaches) the great vows (of monks) and the five small vows (of the laity 3), the five Âsravas and the stoppage of the Âsravas, and control, who avoids Karman in this blessed life of Sramanas, him I call a Sramana.
Śramaṇa in Western literature
Various references to "śramaṇas", with the name more or less distorted, have been handed down in Western literature about India.
Nicolaus of Damascus (c.10 CE)Nicolaus of Damascus wrote an account of an embassy sent by an Indian king "named Pandion (Pandyan kingdom?) or, according to others, Porus" to Caesar Augustus around 13 CE. He met with the embassy at Antioch. The embassy was bearing a diplomatic letter in Greek, and one of its members was a "Sarmano" (Σαρμανο) who burnt himself alive in Athens to demonstrate his faith. The event made a sensation and was quoted by Strabo and Dio Cassius. A tomb was made to the "Sarmano", still visible in the time of Plutarch, which bore the mention "ΖΑΡΜΑΝΟΧΗΓΑΣ ΙΝΔΟΣ ΑΠΟ ΒΑΡΓΟΣΗΣ" (Zarmanochēgas indos apo Bargosēs – The sramana master from Barygaza in India).
Clement of Alexandria (150-211)Clement of Alexandria makes several mentions of the Sramanas, both in the context of the Bactrians and the Indians:
Thus philosophy, a thing of the highest utility, flourished in antiquity among the barbarians, shedding its light over the nations. And afterwards it came to Greece. First in its ranks were the prophets of the Egyptians; and the Chaldeans among the Assyrians; and the Druids among the Gauls; and the Samanaeans among the Bactrians ("Σαμαναίοι Βάκτρων"); and the philosophers of the Celts; and the Magi of the Persians, who foretold the Saviour's birth, and came into the land of Judaea guided by a star. The Indian gymnosophists are also in the number, and the other barbarian philosophers. And of these there are two classes, some of them called Sarmanae ("Σαρμάναι"), and Brahmanae ("Βραχμαναι").
To Clement of Alexandria, "Bactrians" apparently means "Oriental Greek", as in a passage of the Stromata:
It was after many successive periods of years that men worshipped images of human shape, this practice being introduced by Artaxerxes, the son of Darius, and father of Ochus, who first set up the image of Aphrodité Anaitis at Babylon and Susa; and Ecbatana set the example of worshipping it to the Persians; the Bactrians, to Damascus and Sardis.
Porphyry (233-305)Porphyry extensively describes the habits of the Sramanas (whom he calls Samanaeans) in his "On Abstinence from Animal Food" Book IV . He says his information was obtained from "the Babylonian Bardesanes, who lived in the times of our fathers, and was familiar with those Indians who, together with Damadamis, were sent to Caesar"
For the polity of the Indians being distributed into many parts, there is one tribe among them of men divinely wise, whom the Greeks are accustomed to call Gymnosophists. But of these there are two sects, over one of which the Brahmins preside, but over the other the Samanaeans. The race of the Brahmins, however, receive divine wisdom of this kind by succession, in the same manner as the priesthood. But the Samanaeans are elected, and consist of those who wish to possess divine knowledge.
All the Brahmins originate from one stock; for all of them are derived from one father and one mother. But the Samanaeans are not the offspring of one family, being, as we have said, collected from every nation of Indians...
On entering the order:
The Samanaeans are, as we have said, elected. When, however, any one is desirous of being enrolled in their order, he proceeds to the rulers of the city; but abandons the city or village that he inhabited, and the wealth and all the other property that he possessed. Having likewise the superfluities of his body cut off, he receives a garment, and departs to the Samanaeans, but does not return either to his wife or children, if he happens to have any, nor does he pay any attention to them, or think that they at all pertain to him. And, with respect to his children indeed, the king provides what is necessary for them, and the relatives provide for the wife. And such is the life of the Samanaeans. But they live out of the city, and spend the whole day in conversation pertaining to divinity. They have also houses and temples, built by the king".
On life and death:
They are so disposed with respect to death, that they unwillingly endure the whole time of the present life, as a certain servitude to nature, and therefore they hasten to liberate their souls from the bodies [with which they are connected]. Hence, frequently, when they are seen to be well, and are neither oppressed, nor driven to desperation by any evil, they depart from life.
1. For a discussion of this see Chapter Fourteen of Shamanism by Mircea Eliade, Arkana Books, 1989, p.495
2. Dr. Kalghatgi, T. G. 1988 In: Study of Jainism, Prakrit Bharti Academy, Jaipur
3. Flood, Gavin D. (1996) p. 86-90
4. Pande, Govindchandra (1994) p. 135
5. Y. Masih (2000) In : A Comparative Study of Religions, Motilal Banarsidass Publ : Delhi, ISBN 8120808150 ""We know only this much that the doctrine of karma-samsara-jnana-mukti is first seen in the clearest form in the shramanic tradition. It is now even accepted by orthodox brahmans. This doctrine is not clearly spelled out in the Rgvedas and not even in the oldest parts of the Upanishads called chandogya and Brhadaranyaka." Page 149 "The four pillars of Jainism karma-samsara-jnana-mukti have been assimilated into Hinduism. The Pancamahavrata of Jainism (Satya, Ahimsa…) have been fully adopted by Hinduism though not with the same rigour." Page 237-8
6. Gavin D. Flood (1996), An Introduction to Hinduism, Cambridge University Press : UK ISBN 0521438780 P. 86
7. By D. R. Bhandarkar, 1989 "Some Aspects of Ancient Indian Culture" Asian Educational Services 118 pages ISBN 8120604571 p. 80-81
8. McEvilley, Thomas (2002). The Shape of Ancient Thought. Allworth Communications. p. 335. ISBN 1581152035.
9. Jacobi, Hermann (1884). Ācāranga Sūtra, Jain Sutras Part I, Sacred Books of the East, Vol. 22.. http://www.sacred-texts.com/jai/sbe22/index.htm.
10. Ācāranga Sūtra. 1097
11. Ācāranga Sūtra, 799
12. Ācāranga Sūtra 954
13. Jacobi, Hermann (1895). (ed.) Max Müller. ed. Jaina Sutras, Part II : Sūtrakrtanga. Sacred Books of the East, Vol. 45. Oxford: The Clarendon Press. http://www.sacred-texts.com/jai/sbe45/index.htm.
14. Sūtrakrtanga, Book 1: 16.3
15. Sūtrakrtanga, Book 2: 6.6
16. Clement of Alexandria, "Exhortation to the Heathen" 
17. The Stromata, or Miscellanies, Book I, Clement of Alexandria. Clement, Stromatae I, 71,4
18. Porphyry, On abstinence from animal food, Book IV.
19. Porphyry, On abstinence from animal food, Book IV.
20. Porphyry, On abstinence from animal food, Book IV.
21. Porphyry, On abstinence from animal food, Book IV.