Excerpts from Books and Wikipedia
"The heart of Sanskrit learning, however, lay not in natural science but in the study of the literary classics, such as the Ramayana and the Mahabharata. These two epics are concerned with events which took place between 1000 and 700 BC, the so-called Epic era. The Mahabharata as it survives today is the largest single poem in the world. It achieved its final form during the Gupta period with the incorporation of a great speech by the god Krishna. That passage of the great epic is called the Bhagavad Gita and it has become one of the most revered books of the Hindus. The Gita emphasized the necessity for human action in accordance with one's moral duty, thus breaking away from the older doctrine of fatalism, which had suggested that any attempt to change human conditions would be futile." [Nothiger]