Who were the leaders of the indus river valley?

Rulers within the cities of the Indus Valley governed through the control of trade and religion rather than military strength. There is no indication of warfare or weapons that may have been used. The rulers carried seals with animal symbols and writing and wore ornaments of rare material. Each animal symbol represented some form of power: the bull symbolized the leader of the herd, virile and strong; the elephant symbol was attached to goods being traded; the buffalo represented a posture of defense to protect; the tiger was used by minor administrative officers; the unicorn appears to be an important symbol of the elite and was used in governing the different settlements, assuming the economic and political power in the major cities. 

The holy roman empire.