In real world of today, it is visible in some countries of Middle-East where islam and christianity live side by side in one country. And it was also in medieval age in Europe.
Religion wars. Islam vs. christianity, catholics vs. protestantism/orthodox/evangelism ... and so on. Hard to say another good examples.
Various ways of christianity began to accept being of each other. In some countries, very fragile peace/truce is kept by weapons. And in some countries this peace/truce ended in few last years.
But how to prevent religion war(s) when all religions should be allowed (it means, that there will not be situation that one religion will be oficial and other ones banned - like catholics and evangelism in lands of Czech crown between 1621 and 1781)?
In old world, there are three main religions.
- Followers of The Visitor. They believe in reincarnation and they are diligent and therefore very wealthy. Some of them don't like that name because it is a bit derisive.
- Messengers' school. More or less classical church. Pursued by the Creators of the world and The Visitor (gods) because most of them are poor-minded and relying on gods' help too much. Their clerics see deaths of their members as act of Followers of The Visitor (they don't know about eastern part of world, else they would suspect also people living in learning of Desert way).
- Desert way. They believe that gods' help is wrong way and that they will change into Shining ones.