How old is yoga the history of modern yoga asana

The origins of yoga are a matter of debate. There is no consensus on its chronology or specific origin other than that yoga developed in ancient India. Suggested origins are the Indus Valley Civilization (3300–1900 BCE) and pre-Vedic Eastern states of India, the Vedic period (1500–500 BCE), and the śramaṇa movement. According to Gavin Flood, continuities may exist between those various traditions:

This dichotomization is too simplistic, for continuities can undoubtedly be found between renunciation and vedic Brahmanism, while elements from non-Brahmanical, Sramana traditions also played an important part in the formation of the renunciate ideal

Pre-philosophical speculations of yoga begin to emerge in the texts of c. 500–200 BCE. Between 200 BCE–500 CE philosophical schools of Hinduism, Buddhism and Jainism were taking form and a coherent philosophical system of yoga began to emerge. The Middle Ages saw the development of many satellite traditions of yoga. Yoga came to the attention of an educated western public in the mid 19th century along with other topics of Indian philosophy.