At the time Argrath is acclaimed Prince in 1627, Sartar covers some 16,000 to 20,000 km2 (kind of depends on what you want to measure). Pavis is an allied/associated city-state, and is allied with the Pol-Joini and the Praxian Tribes.
Sartar at that time is a little smaller than Massachusetts, and about the size of pre-imperial Macedon, Etruria, or the Kingdom of Israel under the United Monarchy. It is about twice the size of ancient Sparta.
Now that doesn’t sound all that big. But Sartar also doesn’t have that many people – maybe 175,000 in total if we are being generous about what is Sartar. But by the standards of the ancient world, that’s enough. Ancient Sparta (despite being smaller) had somewhere around that many people, while pre-imperial Macedon might have had twice people. Etruria was about in the same ballpark as Sartar.
Remember, a lot of Sartar is to hilly or even mountainous for agriculture. In those valleys, there are lots of farm and villages, but in the rugged hills and mountains, there are flocks of sheep, but not a lot of people.
With the Praxians and the Sartarites together plus their other allies, Argrath can muster a pretty damn tough force with superb cavalry and strong magical support. And because of its position on the main trade route it has wealth. That’s what makes them so important.
