Norse wrote:although I would hazard a guess that he was not of the frankish tribe, just a ruler put in place by the almighty christian empire.
Thats your idea of history all over, really Norse.
His lineage is well documented. He was a Carolingian (after Charles Martel). He has a well documented Frankish lineage. Arnulf of Metz is, I think, the earliest ancestor if particular importance.