Roman Mythology The ancient Greek and ancient Roman religion was the belief in gods. They had similar beliefs, but also vast differences. They came from each other and gave their people a form of morality. It was composed of many meaningful gods and goddesses that all played a part in the everyday life of the average Roman and Greek person of that time. They believed in something called polytheism. It is the belief of many gods; each given a personality, function, relationship to each other through family, and to be the subject of many myths and legends that were to be told for many of years to come. They were to become the basis for a religion that would last