10) For a long time it was believed that Indians are stay at home people and our civilization was only of recent origin. But the excavation at Harappa and Mohenjo-Daro, which led to the dis­covery of Indus Valley civilization, has set all these doubts at naught.Though this civilisation is termed as Indus civilisation it covered even area beyond the Indus Valley. It extended from the upper Sutlej to the Gulf of Camba in the South and from Makran coast of the Arabian Sea in the west to the Jamuna-Ganges coun­try in the east. Thus the Indus civilisation was the largest of the early civilisations.

The Indus Valley, civilisation combines the features of the Neolithic and copper age. The excavation at Mohenjo-Daro have brought to light seven different it layers of buildings, which have assigned to three different period viz., early, intermediate and late. The early layers lie submerged under sub-soil water.

After due consideration the scholars have assigned 500 years to every age, and come to the inclusion that this civilisation must be having an early beginning because it must have taken the people quite a long time to develop such a urban life. Another criteria adopted by the scholars in determining the age of the Indus civilisation is discovery of seals m Mesopotamia, which are dated back to 2500 B.C.On the basis of these seals and other available material the scholars have suggested that the upper most layer belong to the period 230C-2200 B.C. and the lower layers must have belonged to earlier period. Therefore, the period which is roughly assigned to the Indus civilisation ranges between 2500 B.C. to 500 B.C.