If this is a story set in medieval europe kind of setting, none of them. The concept of nationality did not exist before the creation of identification papers. That would be around 1600 or 1700 in our world, IIRC. Before that, it didn't matter where you were born, what mattered was where you, the person feel most attached to. Usually because you were raised there. Unlike the modern world, medieval nations are not permanent. A kingdom can be destroyed within just a few years or become an empire for several hundred years. A kingdom that exist today may not exist next month due to invasions, betrayal, infighting or natural disasters. Serfs back then were technically not free. They were not allowed to leave the land they were contracted to. However, nobody could really stop them from moving in or moving out. Therefore, the concept of nationality was not applicable. Their loyalty was tied to their community and from there, what that community is tied to, such as a king, a kingdom or a city. For example, a hamlet can be within the borders of Filmeria, but identifies more with Rolloria. In the modern world, the hamlet most definitely belongs to Filmeria, because it's within their borders. However, in medieval period before identification papers, the hamlet can very well belong to Rolloria but at the same time it can also belong to Filmeria. The land itself can belong to Filmeria, as there would've been a clear deed of land that identifies where the border is drawn on the map. The people in that hamlet however, belongs to whichever entity they declare allegiance to. EDIT: I forgot to touch on titles of nobility. A knight or baron for example would refer to early version of citizenship. It is because they receive the titles from the king and that kingdom, contracting them to that particular kingdom. An average serf with no title would not really belong to any particular kingdom, because there was nothing tying them to that kingdom. Therefore, who the protagonist belong to in this scenario depends on who managed to give him a binding title first.