The first thousand years of the known history of India was a period of development, and then decline of the Indus Valley civilizations built by the original inhabitants of the subcontinent. However, the next 2,000 years of change were often brought about by groups who came to India across the mountains from the west.(
The first invaders were the Aryan tribes who migrated from Central Asia between 1600 B.C. and 1500 B.C. They brought their religion and culture, which merged with the pre-Aryan civilizations from which grew the Hindu religion and way of life. The Aryan language became the basis of different languages now spoken by most of the people of India. The Aryan tribes that eventually spread across most of India altered the religion, ethnic make-up, and languages of the subcontinent.
In 326 B.C. Alexander the Great led his army of Greek soldiers across Central Asia to invade northwest India, defeat some Aryan kingdoms, and rule over the region. Other Indian leaders realized that their disunity made them vulnerable to attack. After Alexander returned to the Middle East with his armies, Chandragupta Maurya established the Maurya Empire by conquering neighboring kingdoms. His dynasty advanced Indian civilization until it collapsed in 185 B.C.
The Gupta Empire lasted for over two hundred years from its beginning in 320 A.D. Under its leaders, northern India attained a Golden Age of accomplishment in literature, the arts, and science, and a development of mathematics that continues to have world-wide impact. The Golden Age came to an end under attacks by Huns who crossed the mountains from Central Asia. By 550 A.D. they overran northern India, and the period of progress ended.
A remarkable accomplishment took place when one of the cradles of civilization developed in northern India in the Indus Valley. However, much of the later history of India was influenced by groups who invaded northern India from the west across the mountains. They altered Indian culture and language, helped to bring about one dynasty, and destroyed another.
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