The Sanskrit word sutra (सूत्र) is related to the English word suture and means "thread" or "string." Patanjali's Yoga Sutra consists of 196 terse, aphoristic-like sutras divided into four parts or chapters.
Virtually nothing is known about the life or identity of Patanjali, though he is sometimes depicted symbolically as in the statue above. Although there is uncertainty about when the Yoga Sutra was written, many scholars believe it was composed sometime between 200 and 400AD.
Only three of the 196 sutras refer to asana (commonly refered to as "postures") and almost certainly refered to the seated postures of meditation. Contemporary scholarship points to a very recent origin for most of the styles of modern yoga.