A long time ago, before the Common Era, between 100 BCE and 500 BCE, an author named Patanjali compiled the well known yogic text called the Yoga Sutras. This is known to be the philosophical teachings of yoga, composed of 195 (or 196) sutras or threads. Modern day students and teachers study the Yoga Sutras to learn the fundamentals of yoga. It includes asana and yet there is so much more.
The mythological image of Patanjali is a half serpent /half human. This is because Patanjali is known to be an incarnation of Ananta, the Serpent. He was born as a small snake in the offering (anjali) hands of a yogini, praying for a son. He becomes a boy.
Scholars say Patanjali was a sage or a teacher, or the Yoga Sutras might have been written as a collaboration of efforts from a group of yogis. It reveals the nature of the human mind/body, how to live with oneself and with each other, off our mats, in our Life.