The Himalayas helped protect the hunter-gathering people living in what we now call India from the centralising, conquering and consolidating forces of China. But their effectiveness as a barrier decreases further to the north-west, where passes permit the passage of people travelling by foot, horse and chariot. Several waves of invaders came from the north. Some of them probably originated from the steppes of central Asia, from where, having passed through Mesopotamia, they swept into the Ganges plain in northern India, stopped only by the towering Himalayan peaks.
Surprisingly few archaeological remains have been found so far to help piece together the early history of these invasions. Most surviving evidence is literary.
Sacred texts called the Vedas were written in a language called Sanskrit that originated in the Middle East. These texts are thought to describe life between c1700BCE and 1100BCE. They paint a vivid picture of the tools brought by these early invaders in the form of horses, wheels and metal. Their verses talk of noble archers engaged in duels with rival heroes, exchanging volleys of arrows while galloping across fields of battle in horse-drawn chariots. They also describe the use of tools which were employed to clear the jungle around the Ganges Valley. This was a good place to settle. Heavy rains made for lush vegetation, allowing the growth of rice, which could sustain armies.
A superficial reading of some of the ancient texts of India might lead to the impression that these people's destiny was to be as violent as those of the emerging societies to the north, east and west. At the heart of the ancient Indian religion of Hinduism is the Mahabharata, one of the most famous sacred poems ever written.
The Mahabharata tells the story of an epic struggle for the throne of the kingdom of Kuru between two rival branches of a dynastic family, the Kauravas and the Pandavas. The tale's climax is what is said to be the biggest and bloodiest battle in all history: the 18-day Battle of Kurukshetra, in which the Pandavas ultimately triumphed.
The most sacred section, possibly added in about 550BCE, tells of a debate between the leader of the Pandavas, Arjuna, and the god Krishna, who had incarnated himself into human form to serve Arjuna as his personal charioteer. On the eve of battle, Arjuna urgently seeks Krishna's advice as to whether or not to wage war. He has a dilemma: he knows war will mean having to kill various members of his own family, who are obliged to fight against him owing to previous oaths of allegiance.
In this part of the story, called the "Bhagavad Gita", or "Gita" for short, Krishna reveals the mysterious philosophy that still binds Hindu people together and defines their reverence for nature and all living things. He explains to Arjuna that despite the inevitability of war, there is no need to lament those who die in battle, because atman – the spirit of the self – is indestructible. Fire cannot burn it, water cannot wet it, and wind cannot dry it, he says. This self, says Krishna, passes from one body to another, like a person taking off worn clothes and putting on new ones.