At Bodh Gaya Siddhartha Gautama became a Buddha and achieved enlightenment.
He lived for 45 more years, all the while travelling and teaching in cities no more than 150 miles from his birth place
He arrived at the concept of anatman “non-self.”
The Buddha taught that all existence is subject to the law of impermanence and thus reality is a process.
A human being has no permanent essence, only an ever changing relationship of the five skandhas— the physical body (made up of the 4 elements), feelings caused by sensory contacts, perceptions of said contacts (as good, evil, or neutral), habitual mental dispositions (which link mental activity and physical action), and consciousness (experience of the world by mind and body.)
The Buddha opposed both the “indulgence of the wealthy” and “the severe self-denial of ascetics,” proposing instead a middle ground.
The Buddha sought out 5 of his friends from his days as a bhikkhu (a wandering mendicant) and taught them the Four Noble Truths: there is suffering in the world, there is a cause of suffering, by eliminating the cause, one can end suffering, and there is a path by which one can end suffering. (the cause of suffering is sometimes ignorance, sometimes desire)