What is the story of the Hindu faith?

       The history of Hinduism is unique among the world religions in that it has
no founder or date of origin. While most major religions derive from new
ideas taught by a charismatic leader, Hinduism is simply the religion of
the people of India, which has gradually developed over four thousand
years. The origins and authors of its sacred texts are largely unknown.

Although today's Hinduism differs significantly from earlier forms of
Indian religion, its roots date back as far as 2000 BC, making it one of
the oldest surviving religions. Because of its age, the early history of
Hinduism is unclear. The most ancient writings have yet to be deciphered,
so for the earliest periods scholars must rely on educated guesses based on
archaeology and contemporary texts.
In the last few decades, the history of India's religion has also become a
matter of political controversy. The history of any nation (or individual)
is an important part of its self-identity, and this is especially true of
India, which so recently gained independence after centuries of colonial
rule. The controversy over India's history centers on the origin of the
Aryan culture.

The Indus River Valley Civilization

In 1921, archaeologists uncovered evidence of an ancient civilization along
the Indus River, which today runs through northwest India into Pakistan.
The so-called Indus Valley civilization (also known as the "Harappan
civilization" for one of its chief cities) is thought to have originated as
early as 7000 BC and to have reached is height between 2300 to 2000 BC, at
which point it encompassed over 750,000 square miles and traded with
Mesopotamia.
Some writings of this period has been discovered, but unfortunately in such
small amounts that they have yet to be deciphered. Knowledge of this great
civilization's religion must therefore be based on physical evidence alone.
Baths have been found that may indicate ritual bathing, a component of
modern Hinduism. Some altar-like structures may be evidence of animal
sacrifice, and terracotta figures may represent deities. An important seal
features a horned figure surrounded by animals, which some conjecture is a
prototype of Shiva, but it could be a bull parallel to that found on
Mesopotamian seals.

The Controversial Aryans

The Indus Valley culture began to decline around 1800 BC, due possibly to
flooding or drought. Until recently, it was held that the Aryans (an
Indo-European culture whose name comes from the Sanskrit for "noble")
invaded India and Iran at this time. According to this hypothesis, both the
Sanskrit language and the Vedic religion foundational to Hinduism is
attributable to the Aryans and their descendants. The original inhabitants
of the Indus Valley are thought to have had a Dravidian language and
culture, which became subordinate to that of the invading peoples.
Proponents of this hypothesis point to similarities between Zoroastrianism
(the ancient religion of Iran) and the Vedic religion of ancient India, as
well as similar finds in ancient cemeteries in modern-day India and
Tajikistan and Uzbekistan. In addition, no trace of horses or chariots have
been found in the remains of the Indus Valley culture, but were central to
Aryan military and ritual life.
                                        
Since the 1980s, this "Aryan Invasion" hypothesis has been strongly
challenged as a myth propagated by colonial scholars who sought to
reinforce the idea that anything valuable in India must have come from
elsewhere. Critics of the hypothesis note that there is lack of evidence of
any conquest, among other historical and archaeological problems. One
alternative hypothesis is explained by Encyclopædia Britannica as follows:
Between about 2000 and 1500 BCE not an invasion but a continuing spread of
Indo-Aryan speakers occurred, carrying them much farther into India, to the
east and south, and coinciding with a growing cultural interaction between
the native population and the new arrivals. From these processes a new
cultural synthesis emerged, giving rise by the end of the 2nd millennium to
the conscious expressions of Aryan ethnicity found in the Rigveda,
particularly in the later hymns.
The 19th-century Aryan Invasion theory has generally been abandoned as
inaccurate, but most scholars do not reject the notion of some outside
influence on the Indus Valley civilization. For many, it is a political
issue as well as a historical one, with the original theory is regarded as
racist and offensive. BBC Religion & Ethics summarizes the matter this way:
Many people argue that there is now evidence to show that Muller [original
proponent of the hypothesis], and those who followed him, were wrong.
Others, however, believe that the case against the Aryan invasion theory is
far from conclusive.