I have a group of humans who discovered a continent that has no civilisations yet. They settled at a small region and they name their tribe and their lands after one of their Gods. They believed he guided them there, and wanted to honor him.
Over the years, the tribe expands in the region by forming clans. Eventually new tribes are formed, some migrated to further regions and eventually we have the formation of villages, cities, and kingdoms. The setting is fantasy-medieval.
Each kingdom will form their own culture and their own names over the course of thousands of years. But the original tribe will never evolve and become a kingdom. Instead, due to wars over the years they will dissappear completely.
What I would like to do is to have the name they gave to their tribe and land, established as the continents name since everyone originated from this tribe. And have the collective of all humans named after this, even though each will call themselves according to their kingdoms or houses name.
Like in GoT, where the continent is called as Westeros by some, and the collective is called as Westerosi, but they all have different house names. In my case I'd like this to start and be established from the first tribe that was settled on the land.
How can this be done in a way that makes sense during the evolution and establishement of my kingdoms? Note that not all kingdoms or humans will use this name to refer themselves today, but a few will.