Archaeologists were always puzzled by Vedic texts (dated c.1500 - 900 BC) that talked about "nomadic invaders conquering mighty citadels under the banner of their God, Indra". However, no trace of the 'mighty citadels' had ever been found, nor of their mysterious inhabitants, the Dasas.
Then, in 1856, six miles from the river Ravi, in the foothills of the Himalayas, railway construction workers came upon a small crumbling hill of fire-baked bricks. These they quickly appropriated for the railway line's ballast. Along with the bricks, certain steatite (soapstone) seals were found. Archaeologists, notably Sir John Cunningham, quickly confirmed their antiquity. Thus started a voyage of amazing discovery during which archaeologists unearthed the remains of an ancient civilization, which had its epicenter in the plains of the Indus.
Some 5000 years ago, a nomadic people made their way into northwest India from Sumeria (modern day Iran) by means of the Mula Pass across the Himalayas, near modern Karachi, and there found a fabulously rich land, fertilized by the great river systems of the Indus, Ravi, Beas, Chenab and Sutlej. This same area forms modern-day Punjab. Compared to the deserts of Iran, this was God's blessed land, with ample water, fodder and fuel supply. Clay for making bricks was plentiful in the riverbeds and so was wood to burn the bricks.
Over a period of a thousand years, these immigrants spread over an area of half a million square miles
The Indus Valley Civilization (c. 3300 - 1700 BCE, flourished 2600 - 1900 BCE) flourished in the Indus and Ghaggar-Hakra river valleys primarily in what is now Pakistan and western India, extending westward into Balochistan. The mature phase of this civilization is known as the Harappan Civilization, after the first of its cities to be excavated, Harappa. Excavation of Indus Valley Civilization sites has been ongoing since the 1920s.
The peaceful life of the Harappan people bred a sense of complacency. Hence, when the Aryan invaders poured in from the Northwest, they encountered little or no resistance. City after city fell, and the pathetic remains of the people were either assimilated into the conquerors' way of life, or fled further south. In fact, the fall of Mohenjo-daro, almost 3,500 years ago, typified this decay.
In terms of achievements in town planning and civil administration, this was a great setback, as more than a thousand years were to pass before anything of this magnitude was accomplished in India again.
The invaders were a nomadic people, unused to urban life. They revered all natural phenomena, ascribing divinity to animals, the wind, the trees, the sky and the water, among myriads of others. It was during this age that the Vedas began to be composed - this formed the basis of early Hinduism.
