Shastras are the scriptures and treatises on spiritual practices and karma. Darshan is from where the knowledge dawns. The six darshan sastras are:
  1. Sankhya by Sage Kapilar
  2. Yoga by Sage Patanjali
  3. Nyaya by Sage Gautam
  4. Vaisheshika by Sage Kanad
  5. Poorv Mimamsa by Sage Jaimini
  6. Uttar Mimamsa by Sage Vyasa
The second darshan called “yoga darshan” is at first rendered by Hiranyagarba (Brahma). Sage Patanjali preached this darshan in a clear and brief arrangement through his yoga-sutras (aphorisms) in Sanskrit. Just as Vyasa unraveled the gospels on Vedas as Brahma Sutras and Sage Narada offered the Bhakti Sutra, Sri Patanjali Maharishi compiled the yoga sutras.

Sri Patanjali Maharishi made use of few quotations on Vyasa’s Brahma Sutras here and there in His Yoga Sutras. Vyasa’s period is believed to be at the end of Dvapara Yuga, followed by Kali Yuga. Therefore, the existence of Patanjali can be traced to the end of Dvapara Yuga (before 5000 to 6000 years). Hence, it is logical to think that both Vyasa and Patanjali lived contemporarily. Vyasa’s commentary on yoga sutras called Bashya is still in vogue. From this, it can be inferred that Patanjali Maharishi would have lived before Kali Yuga and presented the Yoga Sastras during that period.
Sri Patanjali’s father is Sage Atri. Hence, Patanjali is named after his father as Atreyar. His mother’s name is Gonika. Therefore, he is also known as Gonika putra (Gonika’s son).
Patanjali had given three phenomenal Shastras to the world. They are:
  1. 195 Sutras for Yoga Sastra
  2. Yoga Sutras demonstrate the ways to conquer our mind through concentration and purity. Therefore, Yoga sutras are highly beneficial to humanity.
  3. Mahabhashya (Grammar) for Vyakarna (A grammar work by Vyasa)
  4. For sounds and words, Mahabhashya is of great aid. It helps us to speak without errors and benefits us with the sound produced from speech.
  5. Charaka (a system of medicine) for Ayurveda (a form of upaveda) (Ayurveda Charaka is also known as Atreya Samhita)
  6. Ayurveda Charaka or the Atreya Samhita is useful for curing wounds and ailments. (At the body or physical level)
Therefore, the Yoga Sastras deals with Mano-Vaku-Kayam (Thought-Word-Deed).
In one instance, 1000 students across the world gathered at the thousand-pillared hall in Chidambaram, to learn Mahabhashya from Patanjali.  Sri Patanjali had assumed the form of thousand-headed Adi Sesha. Adi Sesha put a partition with a screen between him and his disciples. Before he began his teachings, he laid forth the following conditions to his disciples:
  1. The disciples should immediately clarify the doubts that creep in their minds. None of them should not peep into the screen and try to look at Him. Because, the radiant flames from his thousand heads could burn the disciples to ashes.
  2. Nobody should step out of the hall until he finishes his discourse. If they step out, they will become demon-Brahma Rakshasa.
Out of the 1000 students, 999 of them who violated his conditions were burnt to ashes. However, a dull-witted student named Gaupada (from the place of Gauda), who had gone out for a while during the course of the lecture, survived from the flames of Adi Sesha. Since he violated the second condition, he became a brahma rakshasa. Later Sri Patanjali imparted the knowledge to Gaupada and bestowed his grace. Sri Patanjali also released Gaupada from the curse of being a brahma rakshasa.
Patanjali – Name forms and avatars (incarnations) 
  1.  It is already mentioned that he came to be called as Atreya and Gonika Putra.
  2.  From the story narrated above, we know that he assumed the form of Adisesha.
  3.  We all know that Lord Shiva assigns the responsibility of creation, Protection and destruction respectively to Brahma, Vishnu and Rudra. Sri Patanjali is the resting seat of Lord Maha Vishnu, the one amongst the Trimurti, who was vested with the responsibility to protect the Sovereign of earth by Lord Shiva.
  4. Lord Shiva holds Sri Patanjali as His ornaments (in the form of snake) in various parts of His body.
  5. In Krita yuga, Sri Patanjali did service to Indra.
  6. He incarnated as Lord Rama’s younger brother, Lakshmana in Treta yuga. He slew a demon named Indirajit to death.
  7. In the Dvapara yuga, Patanjali incarnated as one of the Pandavas, Bima, the younger brother of Dharmar. In Kali yuga, He killed Duryodhana and achieved a triumphant victory.
  8. Sri Patanjali also incarnated as Balarama, one of the ten avatars of Maha Vishnu.
  9. Sri Patanjali assumed the avatar, Govinda Gaupada, to preach Advaita to Adi Sankara.
  10. Sri Patanjali incarnated as Thirumoolar, who composed Thirumantiram. Thirumantiram is a work in Tamil, which contains 3000 mantras, each comprising 4 verses. It reflects the 195 yoga sutras compiled by Patanjali in Sanskrit.
The Yoga Sutras comprises of four parts or padas namely,
  1. Samadhi Pada
  2. Sadhana Pada
  3. Vibhuti Pada
  4. Kaivalya Pada
Every individual, in the end, aims to attain salvation. This state is what we call in yoga as Samadhi or Kaivalya or the Absolute state. Lord Shiva had detailed the ways to attain this Supreme state to Lord Brahma. Yoga Sikha Upanishad deals with it in detail. The Upanishad begins with Brahma posing a question to Lord Shiva:
 “Oh Shankara! The embodiment of divine effulgent light! All the living beings are surrounded by illusion. How will they get liberated? Kindly show us the path to cut the illusive net and to attain Supreme bliss”.
 Lord Shiva answered Lord Brahma’s question as below:
 “Brahma! The one born out of lotus flower! It is difficult to realize The Self (attaining mukti) by resorting to different means. However, it is evident from Sages’ lives that mukti can be reached through yoga. There is no other path to perfection.”
Lord Shiva very clearly pointed out in the above verses that yoga alone leads one to salvation. Therefore, we need to inquire the mystery behind these verses and strive to follow its teaching in our life in order to attain salvation.
The evidence of these truths are found in:
  1. Sri Shankara Vijayam
  2. Paatanjala Yoga Sutra by Pandit Kadalangudi Natesa Sastri, Chennai
  3. Yoga Sutra by Sri C.Subramaniya Sastri
  4. Yoga nadi by Pathanjali Nadi Kendra