Great read and very informative, TheHoarseWhisperer. I'm currently redrawing my maps from a tight focus on a singular region to the broader top-down view of the entire continent. I'll be incorporating many of your ideas and comments into the recreation of my world.

One comment on the expansion of empires: religion. I don't believe this was mentioned previously. A good example are the Crusades. While there may have been natural resources or military advantages to the capture of Jerusalem, the city and region hold religious significance for three major religions. The battle for control over this region has persisted to this day due to religion.