L3T doesn't provide any historical ressources distribution. Main cause is that we aim for compatibility with various maps, so we can't attach a ressource to a province ID. Other reason is that it would a huge amount of research and short-lived code since Paradox continues to add or tweak provinces each patches.I'm curious.. what has now become the most valuable county (not looking at holdings)? Constantinople, Baghdad, Basra and others were so rich and strong, yet they lack resources. While empourie somewhere in Aquitaine, a little county has minerals, stone and more.
Also, is there any gold in, for example, Tirol or la mancha?
Reason I'm asking is since I want start the establishment the capitals of capitals as Haesteinn, preparing an invasion on Asturias as I'm typing. Going for Lugo at the moment, gambling on the improve holding slots and amking use of the river, coast and resources available. Not to mention the vast forest and location might make Haesteinn miss home a little less and it is ofcourse a good landing spot for him and his longships.
Not sure why you said "has become", this was always like that in L3T, it is not something that we'd plan to change.