i tend to play spain a lot. in my opinion, any faction that owns the entire iberian area can expand really fast. even without trade.

at 80% agriculture developement, the entire iberian area seems to be "high income" areas.

compare this to other factions i played, besides the muslims, the central/northern europe areas seems to be plagued with low income areas. not sure abt eastern europe.

the muslims have it better generally speaking. but take out the mines from the north african areas and dun forget crap areas like sinai and arabia.

so as a whole. any AI owning the iberian areas will become a power. (and also iron deposits)