Patanjali is the second century CE author of the Yoga Sutra, explaining the moral and physical disciplines necessary for liberation.
Biography from Saints, Sufis and Yogis
The Patanjali of the second century CE was the compiler of an historically important collection of sutras (verses) on yoga. Whilst there had been earlier breath control and meditation traditions, Patanjali was the first to bring a systematic yoga into textual form in his Yoga sutras.
This Patanjali is different from the earlier grammarian of the same name.
Yoga is the cessation of the turnings of thoughts. (Yoga Sutras 1:2)
The Yoga Sutras were widely copied in the ancient and medieval periods, being translated into forty Indian languages and two non-Indian languages: Old Javanese and Arabic. In the modern period the text has been translated into English and other western languages, and continues to be popular and widely studied, particularly in the physical yoga culture of the USA.
Bibliography: Edwin F.Bryant, The Yoga Sutras of Patanjali (New York: North Point Press, 2009); Christopher Key Chapple, Yoga and the luminous: Patanjali's spiritual path to freedom (Albany, NY: State University of New York Press, 2008); P.Y.Deshpande, The authentic yoga: a fresh look at Patanjali’s Yoga Sutras with a new translation, notes and comments (London: Rider, 1978); Mircea Eliade, Patanjali and yoga (in French, 1962; New York: Funk and Wagnalls, 1969); Geoffrey Samuel, The origins of yoga and tantra: Indic religions to the thirteenth century (Cambridge, UK: Cambridge University Press, 2008):221-223; Jeffrey Clark Ruff, History, text, and context of the 'Yoga Upanisads' (Doctoral dissertation, University of California, Santa Barbara, 2002):17-18,256; David Gordon White, The Yoga Sutras of Patanjali: a biography (Princeton: Princeton University Press, 2014)