in Jain and Buddhist texts . Between 200 BCE and 500 CE, traditions of Hindu, Buddhist, and Jain philosophy were taking shape; teachings were collected as sutras, and a philosophical system of Patanjaliyogasastra began to emerge. The Middle Ages saw the development of a number of yoga satellite traditions. It and other aspects of Indian philosophy came to the attention of the educated Western public during the mid-19th century. Origins Linear model According to Edward Fitzpatrick Crangle, Hindu researchers have favoured a linear theory which attempts "to interpret the origin and early development of Indian contemplative practices as a sequential growth from an Aryan genesis"; traditional Hinduism regards the Vedas as the source of all spiritual knowledge. Edwin Bryant wrote that authors who support Indigenous Aryanism also tend to support the linear model. Synthesis model Heinrich Zimmer was an exponent of the synthesis model, arguing for non-Vedic eastern states of India. According to Zimmer, Yoga is part of a non-Vedic system which includes the Samkhya school of Hindu philosophy, Jainism and Buddhism: "[Jainism] does not derive from Brahman-Aryan sources, but reflects the cosmology and anthropology of a much older pre-Aryan upper class of northeastern India [Bihar] – being rooted in the same subsoil of archaic metaphysical speculation as Yoga, Sankhya, and Buddhism, the other non-Vedic Indian systems." Richard Gombrich and Geoffrey Samuel believe that the śramaṇa movement originated in non-Vedic Greater Magadha. Thomas McEvilley favors a composite model in which a pre-Aryan yoga prototype existed in the pre-Vedic period and was refined during the Vedic period. According to Gavin D. Flood, the Upanishads differ fundamentally from the Vedic ritual tradition and indicate non-Vedic influences. However, the traditions may be connected: The ascetic traditions of the eastern Ganges plain are thought to drew from a common body of practices and philosophies, with proto-samkhya concepts of purusha and prakriti as a common denominator. Indus Valley Civilisation The twentieth-century scholars Karel Werner, Thomas McEvilley, and Mircea Eliade believe that the central figure of the Pashupati seal is in a Mulabandhasana posture, and the roots of yoga are in the Indus Valley civilisation. This is rejected by more recent scholarship; for example, Geoffrey Samuel, Andrea R. Jain, and Wendy Doniger describe the identification as speculative; the meaning of the figure will remain unknown until Harappan script is deciphered, and the roots of yoga cannot be linked to the IVC. Earliest references (1000–500 BCE) The