pre-Harappan phase was found here for the first time. This work soon gained
support from the work at Amri in Sind and the work at Kalibangan in the
dried up Ghaggar valley. By the early sixties, more meaningful
archaeological discussion on the origin of the Indus civilisation became
possible, as was evident from a new theory of origin. There is every
justification for regarding the Kot Dijian, Amri and Sothi (Kalibangan)
cultures as not only pre-Harappan, but also ‘proto-Harappan’ cultures. But
there was still a controversy about the mechanism of origin, because it was
linked to the diffusion theory. The form of the civilisation, according to it,
was the result of a deliberate choice made by ‘a few genius-dictators’ who
‘borrowed the idea of cities from the contemporary Sumerians and promoted
foreign trade and standardisation to gain prosperity.
  In the early fifties, theories about the origin of the Indus civilisation
  ranged from the then somewhat weak theory of indigenous origin (since
  origin outside India was considered to be ‘inherently improbable’) to the
  more popular foreign origin theory in the form of a wholesale or
  piecemeal import from Elam (South Western Iran) and Mesopotamia. In
  between these two extreme opinions was the theory of ‘stimulus
  diffusion’, which is also based on the premise of migration of civilisation
  from Mesopotamia to the Indus. We should also keep in mind that it is
  from this time that the Indus civilisation began to be conceived of as
  something fertilised by Mesopotamia in particular and West Asia in
Compromise Theory In late sixties, attempts were made to explain the
proto-historic cultural growth in Baluchistan and the Indus system in terms of
a few developing ‘phases’ or ‘stages’. The Harappan civilisation, according
to this theory, is said to have achieved its characteristic style indigenously; its
elaboration, however, may have been the outcome of Sumerian contact.
Revival of Foreign Origin Theory by Highlighting Role of Trade In the
early seventies, a new dimension was given to the controversy. The most