The post-Mauryan period saw the rule of the Indo-Greeks, Shakas, Pahlavas and the Kushanas in North India. This tells us that there was no central authority that could keep the country together at the face of foreign invasions. The small dynasties remained engulfed in their mutual petty warfare, giving the chance to the aliens to invade the land. It can be stated that the lack of an united approach provided chance to the foreigners to establish their rule in the Indian soil.