What is the role of religion in the ancient world?

Answer 1

In the Ancient World, religion was central in most cultures as it provided answers to the difficult questions, cemented the validity of the ruling chieftains and statesmen, and defined the country as one united polity.

Answer 2

The question is too broad to give more than a very general answer. The 'ancient world' encompasses many centuries, perhaps traditionally two millennia, during which time religions evolved, as did their impact on societies. The implied geographic scope must at least include all of Europe and the Middle East, once again including a huge variety of beliefs and practices.
One constant is that religion helped to define the society. If you worshipped this god, then you must belong to this culture. If a culture was conquered, this was often accepted as meaning that the old gods of the conquered nation were weaker than those of the conquerors, and so these gods were adopted. And, when new gods were adopted, the old ethnic boundaries were removed.

Most ancient societies were intensely religious. All around the Mediterranean, archaeologists have found numerous temples, holy sites, sacred statues and other evidence of the importance of worship in the daily lives of the people.