The people in the prehistoric times used tools and weapons made of stone. Later man started using metals. Copper was the first metal to be used by man for making tools. Gradually several cultures developed in Indian subcontinent which were based on the use of stone and copper tools
They also used bronze, a mixture of copper and tin, for this purpose. This phase in history is known as the Chalcolithic (chalco-Copper; lithic-Stone) period. The brightest chapter in the Chalcolithic period in India is the Harappan civilization which is also referred to as the Indus Valley civilization.
Harappan civilization was discovered in 1920-22 when two of its most important sites were excavated. These were Harappa on the banks of the river Ravi and Mohenjodaro on the banks of the Indus. The first was excavated by D. R. Sahani and the second by R.D. Bannerji.
On the basis of the archaeological findings the Harappan civilization has been dated between 2600 B.C-1900 BC and is one of the oldest civilizations of the world. It is also sometimes referred to as the ‘Indus Valley civilization’ because in the beginning majority of its settlements discovered were in and around the plains of the river Indus and its tributaries. But today it is termed as the Harappan civilization because Harappa was the first site, which brought to light the presence of this civilization.
Besides, recent archaeological findings indicate that this civilization was spread much beyond the Indus Valley. Therefore, it is better it is called as the Harappan civilization. It is the first urban culture of India and is contemporaneous with other ancient civilizations of the world such as those of Mesopotamia and Egypt.
Our knowledge of the life and culture of the Harappan people is based only on the archaeological excavations as the script of that period has not been deciphered so far.
The Harappan civilization did not appear all of a sudden. It developed gradually from earlier Neolithic village cultures. It is believed that the better technology to exploit the fertile plains of river Indus might have resulted in increased agricultural production. This led to the production of larger surplus to feed and maintain non-agricultural people such as artisans, administrators, etc. It also helped in the promotion of exchange or trading contacts with distant regions. It brought prosperity to the Harappan people and they were able to set up cities.
By around 2000 BC several regional cultures developed in different parts of the subcontinent which were also based on the use of stone and copper tools. These Chalcolithic cultures which lay outside the Harappan zone were not so rich and flourishing. These were basically rural in nature. The origin and development of these cultures is placed in the chronological span between 2000 BC-700 BC. These are found in Western and Central India and are described as non-Harappan Chalcolithic cultures.