It is believed that 3500 BCE yoga was already being practiced based on a seal found in indus valley showing a man sitting cross legged.
Yoga is said to have been practiced in India since then in one form or another. Between 1500 and 500 BCE the Vedas were written down and Vedic culture which turned into Hinduism was practiced.
Around 600 to 400 BCE the Upanishads part of the Vedanta were created. It is not quite clear by whom but they are papers seeking to answer philosophical and meta philosophical questions.
Around 500 BCE two further forms came along Buddha and with him Budhism and the Bhagavad Gita both more accessible forms and breaking with the cast system more and more.
All of these forms were still Vedantic forms of yoga and had the sacrifice of the physical being in favour of the spiritual rise as a basis.
300 to 400 BCE the Yoga sutras were collated by Pantanjali.
Around 100 to 300 AD Tantra Yoga developed which aimed at an inclusion of the spiritual and the physical being a form of balance.
Around 800AD the principle of non dualism in yoga was developed, in terms of no separate god, we are all one, as god is in everything both in Vedanta and Tantra.
All these forms however still were mainly meditation based forms of Yoga, the first hatha yoga text was developed in 1350AD. Asana and pranayama practice only became popular in recent centuries.
Yoga mainly was practiced in India and wider Asia however in 1893 Vivekanada made his way to the states to attend the world parliament of religion to speak about Yoga and how it was a universal religion. This is said to have been one of the main introductions of yoga into the west. Vivekanada had been a disciple to a guru called Ramikrishna. The latter was originally mainly devoted to Khali but later on, in trance like states, had experiences of various religions and concluded all religions sought bliss.
Yoga is said to be the seeking of ultimate truth, however it also appears to be a way of life, a bit like a religion, the main part known to the majority of people to some extent is that there is a physical practice called yoga. People practicing the physical practices in class will be aware of the asana and pranayama. However there are further parts of yoga the ethical and spiritual part and the meditation practices.
The ethical practices are split in five yama’s and niyama’s which act a bit like the ten commandments. The five yama’s are things one should not do. While the five niyamas are things one should aspire to. The five yama’s are non – violence, don’t lye, don’t steal, sexual moderation and don’t be greedy. Following the niyama’s one should aim for purity, contentment, discipline, study and devotion.
The four parts of meditation practice are withdrawing the senses, concentration, meditation and absorption. They are all states of consciousness which have been found by yogis thousands of years ago to exist while today they are proven to exist in terms of various frequencies within the brain.
While yoga today is meant to be union of body and mind there is also an aim to understand that the body is the vehicle of an energy i.e. the spirit.
The physical practice of asanas and the breath control are part of a discipline but ultimately are aimed to still the mind. The result of that stillness of the mind is the experience of truth.
The ultimate goal of all three parts of practice is for the being to connect and find its inner spirit the Atman and to connect to the eternal spirit the Brahaman. An overcoming of human natures ego and cultural restraints, a form of letting go of materialistic goals as well as intellectual knowledge acting as boundary to the connection of said spirit.
The stilling of the mind via asanas, breath control and meditation to me is the main draw to Yoga, however not necessarily for the goal of truth or the enlightening or finding of Atman or Brahman. Yoga’s ability to counteract the drain that today's way of living has on everyone, is what has drawn me most to it. The fact that asana’s, breath control, meditation and a control of consciousness can act as stress release and counterbalance is most interesting to me.