Rudiments of ancient Indian history have indeed been available to Indians for thousands of years, but it is impossible to arrange them in a chronological order or to differentiate history from mythology and traditions from imaginations. The sculptures and the inscriptions that are passed on to us tend to glorify the kings or the donors and it is hard to cross check the validity of some of the claims found in them. Much of the foreign sources on India, namely the travelogues of explorers have been assembled through second hand information and it is difficult to differentiate realities from hearsay. How we know what we know Literature References to historical events and traditions are scattered in many ancient Indian texts, even in the mythological Ramayan and Mahabharat , the Hindu epics believed to be of divine origin. We have to even consider unlikely resources of grammar books of Panini and Patanjali for hidden historical references and events.
Some biographies are available.
However glorifying is the language, they do provide deep insights into the great historical persons they illustrate. The monuments spread all over India are undying witnesses of the artistic skill of ancient Indians and testify to their wealth and grandeur at various epochs of history. They also give us an illustrated view of the period cultures than it is possible to cull from works of text. The Greeks who accompanied Alexander the Great in his Indian campaign recorded their encounters of this mystical, magical land. Although much of these works are now lost, the details have percolated into subsequent Greek literature.