[quote=Monkeypants]
Happy to see my historical period method is now in use on another ns :D I had fun when I was doing it.Edit:Ok, so no one gets all pissy over territory, I have two versions of a map. The one I posted is the bigger of the two. The reason I had a large portion of land is because this is continent is only the size of asia, I figure middle ages nations were pretty big in Europe so I went with a larger nation. just give me some input..Also, on population. In 117 AD (far before the middle ages), the roman empire had an estimated 88 million. Populations are going to be much bigger than the 100 mil mentioned in an earlier post. (Not that the numbers really matter that much anyway.)
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Medieval kingdoms weren't often that big, and they were more often messy than they were clean in the modern era. Especially the larger Arab ones akin to the pre-Ottoman dynastic empires like the Ummayads and the Abbasids. Those in all reality had such loosely defined borders compared to the Kingdoms of Francia and Italy you couldn't really help but not draw their borders in a heavily blended and very fuzzy felt-tip marker, and then refer to them by the dynasty name.

Same applies to India, which through most of its history post-[url=https://en.wikipedia.org/wiki/Ashoka]Ashoka[/url] history was really a bunch of fragmented kingdoms and smaller kingdoms.

More often larger kingdoms were liable to loose a fair bit of territory on succession. Either because vassalage is generally sworn to the king who passed, or because succession deems it important that the King's sons get an even - or, sort of even - distribution of their father's demesne. Charlemagne's [url=https://en.wikipedia.org/wiki/Carolingian_Empire]Carolingian Empire[/url] was divided up much the same way. It wasn't so much a collapse as it was dividing it up between his sons or relatives.

You could point to the Carolingian Empire and make the claim that in Post-Rome Europe there weren't many massive and centralized kingdoms or Empires anymore. Feudal investiture had a thing to keep up a lot of smaller states. Even the Holy Roman Empire wasn't even that centralized, and at least before the Hohenstaufen reforms lacked anything close to stability.

In terms of sheer geographical size the Cumans probably came closest to the "large empire" thing pre-Mongols (which was subject to similar succession rules as Charlemagne). But that could probably be looked at as more of a loosely united stretch of steppe in the Caucus and Central Asia inhabited by the Turkic Cumans.