Military action
The Tribal Wars refer to the time before Kingdoms and after the first development of human social groups when each tribe had their own beliefs and they would have skirmishes with other tribes of different beliefs. These could be small, about land or large about spreading ideology. The larger ideologies of course still exit today in different forms.
About 300 years after the beginning of the Tribal Period a small splinter group from an island near the Continent came to the biggest waring area. They called themselves Followers of Or and they named the continent Orori thinking they could practice their religion in freedom away from the mother religion that had been trying to get rid of them. The tribal disputes raged though and the religion couldn't find a place that wasn't claimed along the habitat shore they landed on, so they spread their religion as best they could until they became the largest tribe on Mandor. 450 years after the Followers arrived on Orori the first Kingdom was founded and a New Era began.