The men in charge controlled what the people were told about rival populations, the history of their tribe and its leadership, etc. When the written word was invented, men in charge dictated what books were permitted to be written and circulated, what ideas were allowed, what narratives the public would be granted access to.

This continued straight on into modern times. Where power is not overtly totalitarian, wealthy elites have bought up all media, first in print, then radio, then television, and used it to advance narratives that are favorable to their interests. Not until humanity gained widespread access to the internet has our species had the ability to freely and easily share ideas and information on a large scale without regulation by the iron-fisted grip of power.