The de Warenne tree is a mess and it seems to be because of a conflict of historian theory so I need to ascertain which is better sourced. So far we have
1. Medlands which the curators for the most part trust because it lists sources where they exist.
2. Warren researcher, Norma Kirchhofer
I have not heard of Norma Kirchofer before and would like to know more of her sources.
The two conflicting theories seem to be as follows:(according to Norma Kirchhofer)
The father of William Warren, who ultimately became first earl of Surrey, was also called William but he was never earl of Normandy but rather Count of Varenne. There were no earls in Normandy although the title of count is of similar status and is an exact dictionary translation. The first earl's grandfather was Walter de St. Martin and his g.grandfather was Herstafus & his father was Rollo A Danish Knight.
There was another pedigree circulating some time ago which gave the father of William Warren (1st. earl of Surrey) as Rudolph, whose father in turn was supposedly Hugh, Bishop of Coutances. To the best of my knowledge this has long since been disproved by the charters of Rouen which are presently kept in the National archives.
Unless someone can produce a source I will have to 'fix' the tree to agree with Medlands with notes about the conflicting theory.