I'm not sure of that. The North Coast has been consistently inhabited by humans for one of the longest periods of time, and seems to be one of the areas of Europe least affected by the various migrations, conquests, etc., at least in terms of culture. At least, so my reading would lead me to believe.
well...you are right, as far as i know Romans had lots of difficulties to enter here because people in here were ( and still are) pretty closedand they used to live in the mountains shown on the pictures posted above so it was not easy to find them, they lived in little villages and did not mind to stay in the forrest...but finally the Romans came, never were welcomed but they were more..
I also know that Romans hired people from the north coast as mercenaries in battles because apparently they had a very bad mood and temper and did not really mind to die or be caught because they always carried a piece of one tree that kills you so when they were caught or when they were old( therefore un-useful) they ate that tree and kill themkselves..
when arabs come they conquered all Spain except the north coast because they could never crossed the mountains, the guys were in little armed groups and did what is after that known as guerrilla, so arabs never came in here..
and we got the altamira caves here as well, so people were in here since the beginning..
However in terms of old culture stuff Mediterranean area cracks, the have (ok, few names in spanish ) tartessos, fenicios, greeks,romans,arabs..and basically everybody from the ancient times as it was a nice place
) ) full of metals, nice weather, food..so if you do a cultural trip the south is nice...
But if you are more intested in celtiberians then north is better...and definitely food here beats all
which is a nice excuse to visit us