The gods of the Aryans: from 1500 BC

The first traceable roots of Hinduism lie with the invading Aryans, who move into the northwest of the Indian subcontinent from about 1500 BC (see the history of India for recent archaeological arguments against the concept of an Aryan invasion). The Aryans' priestly caste, the Brahmans, are responsible for the sacrificial rites (the most solemn, among this nomadic people, being the sacrifice of a horse). The ritual hymns which they chant, passed down orally for many centuries, are gathered in the rigveda, the earliest of all religious texts.

The hymns of the rigveda reveal that the foremost god of the Aryans is Indra, a war god and a great slayer of demons and animals. He is possibly based on a historical leader of the Aryans in their advance into India, for one of his titles is 'city-breaker'.

The two other main gods of the Aryans are Agni, the god of fire; and Soma, a god associated with a drink (also called soma and probably hallucinogenic) which plays a major part in the priests' rituals. In the long term none of these gods feature prominently in Hinduism. But two minor characters are waiting in the wings for a major role.

Vishnu appears in the rigveda as a sun god who occasionally helps Indra to slay demons. And Shiva (under the name of Rudra) has a small and sinister part, prowling in the mountains, shooting humans and animals with his arrows, and both causing and curing disease.

Vishnu Shiva and Brahma: from 300 BC

By about 300 BC, when Indian myth and folk tale begin to coalesce in the mahabharata, Vishnu and Shiva are emerging as the main Hindu gods. In most ways they are direct opposites of each other. Vishnu is associated with creation, Shiva with destruction - though in the eternal cycle of events destruction must precede the next act of creation, so there is not the clear moral difference between the gods that the words would normally imply.

But opposites do require a middle way, a reconciliation. This is provided by a new god, Brahma, who by the 1st century BC emerges as the central and senior figure in the Hindu trinity. He therefore acquires the role of creator (Vishnu becoming the preserver, and Shiva remaining the destroyer). Brahma's name clearly relates to the Brahman, the priest. It is thought perhaps to have been a key word in sacrificial incantations.

Brahma has had no popular cult in India, for he is in a sense the godhead behind all the other gods. But Vishnu and Shiva become conclusively established as the two main deities of popular Hinduism. The majority of temples in India today are sacred to one or the other.

Temples to Vishnu are often not directly linked with his name, for he is believed to have had many different incarnations and he is usually worshipped as one of these. By far the most popular of these incarnations, or avatars, are Krishna (associated with the influential Bhagavad Gita) and Rama.

By contrast, temples to Shiva take a standard and easily recognizable form. At the entrance there is invariably the reclining figure of Nandi, the sacred bull who carries Shiva on any journey.

Raised on a platform, Nandi gazes into the central shrine of the temple where the lord Shiva is represented in symbolic form as a rounded stump of stone - the linga, or phallus - to which priests and pilgrims make offerings of flowers, fruit and rice.

The colourful polytheism of popular Hinduism is the glitter on the surface of a faith which is essentially ascetic. As with the other religions originating in India (Jainism, Buddhism, Sikhism), the ultimate purpose of any devout Hindu is to escape from the recurring pattern of existence.

The tally of a person's life is his or her karma (action). This is the total of the good works or sacred practices which have been carried out. In the short term a good karma will lead to reincarnation in more fortunate circumstances, or in a higher caste. Eventually it may make possible the ideal, which is moksha ('release' from this earth and from the cycle of rebirth).

Hinduism in southeast Asia: from the 1st century AD

Traders from India, increasingly adventurous as seafarers from the 1st century AD, carry Hinduism through Southeast asia. On the mainland (Burma, Cambodia, the southern part of Vietnam) and in the islands (Sumatra, Java), Hindu kingdoms are established. In later centuries impressive Hindu temples are built. Angkor wat is merely the best known.

As in India itself, Hinduism and Buddhism coexist in the early centuries. In Southeast asia, Buddhism eventually prevails and Hinduism fades away (except in the small island of Bali). In India, by contrast, Buddhism vanishes in its homeland - leaving the field to the subcontinent's first great religion, Hinduism, and to a newcomer, Islam.