Rollo - Count of Rouen

In the discussion of the Normans and England, William the Conqueror's parentage needs to be understood.

Also, those that were involved in the Conquest needs a little more explaination. In particular, the relationship of the de Veres to the decendants of Rollo.

The Dukes of Normandy

The English Kings

Was de Vere the Brother-in-law of William the Conqueror?

The "not related by marriage" is in line with my contention but there seems to be not recorded account of a de Vere accompaning William to England.