Decline of the Bronze Age Civilisation:

We find that the great developments in production methods that came with the rise of early cities lasted only f6r a few centuries. The initial burst of technical advance was followed by a long period of stagnation. Cities arose and fell; one dynasty of priest-kings overthrew another. But there was no change in the pattern of production. It remained based on irrigation agriculture, supplemented by  trade with other cultures. This, probably, happened because in this process the social organisation had also changed. In the primitive human society no special groups existed, whereas there now came into being different strata in the society.  As we have seen earlier in Sec.there arose a division between those who produced and those who appropriated the produce.  This also meant a division betweefi the thinkers and the doers, between theory and practice.  We have also seen how this led  to stagnation  in science. Eventually,  the social structure became exploitative. Peasants and urban craftsmen became poorer, many of them ending up as slaves later on.  The emergence of two distinct classes, the haves and the havenots, in the society, led to conflicts between them.  This weakened the city states and ultimately put a stop to their intellectual and technical progress. Increasing population an3 continuous barbarian invasions also brought tremendous pressure on these city cultures.  They had to expand  territorially to occupy more available land, in order to feed the population. They also had to raise armies and fortifications  to defend themselves. Even  in  the Indus Valley, which was a non-violent culture, fortifications were raised in the later days. Fortifications, walls and other instruments of violence such as catapults and moving towers required  the application of mechanics. As wars became a part of  life, aney group of professionals  came into being. They were the persons who invented and made new war machines and built defensive and offensive structures. They may have been  the forerunners of  the engineers of  today.