When we think about the size of Genertela, remember that it is roughly 5000 km long from west to east and 1700 wide from north to south. It is a little bit bigger than the continguous USA or Australia, and a bit smaller than the entire European subcontinent.
Genertela is MUCH smaller than Eurasia. Heck, all of Glorantha – Pamaltela, Genertela, East Islands and the oceans – all of it together is a bit bigger than Eurasia.
Dragon Pass covers about 67,000 square kilometers. That’s a little smaller than Austria. Or a little bigger than West Virginia.
Prax itself is about the size of the Mojave Desert or the semi-arid Columbia Basin.
So if you think about the Lunar Empire, it covers about 390,000 square km, or about 5% of Genertela. That still is enough to make it the largest empire in Genertela.
But even so, the Lunar Empire is comparable to the size of modern Germany (it is a bit bigger). It is not the Roman Empire (which would cover 75% of Genertela).
If we assume that Kralorela is about 1250 km km long and about 350 km wide, then it roughly comparable in size to the Lunar Empire (once we compensate for the Suam Chow). So lets say both are roughly the same size as Iraq.
One of the things I really like about the scale of Genertela is means that every part of the continent has some contact with the rest of the continent. Let’s give a real world example – Pre-Columbian North America had extensive trade with Mesoamerica, and we know that the Mississippi River Valley facilitated trade between Wisconsin and the Gulf of Mexico. The Iroquois of the 18th century were known to travels from the St. Lawrence Seaway to the Carolinas to wage war on the “Flatheads” (aka the Cherokee, Choctaw, Chickasaw, etc.), as far as 1000 km away. In Glorantha that’s roughly about the distance from Glamour to Boldhome.
We know that Kralorelans sometimes travel to Dragon Pass and vice versa. Balazarings sometimes make their way to Prax. Merchants from the Holy Country can be found in almost every corner of the continent. People from the Lunar Heartlands make their way to Fronela and Ralios. And so on. The various cultures in Genertela are not hermetically sealed.