Roger de Condé - Sources?

I think this is probably based on an Ancestry.com tree, which may be fact-based or may be wishful thinking: http://records.ancestry.com/roger_de_conde_records.ashx?pid=4644819

A French source (Précis de l'histoire d' Avesnes) claims that Wederic had three children: his heir Thierri, a son Gerard who went on the First Crusade (and may not have come back), and a daughter Ada or Ida, who married Fastrade d'Oysy. No Roger.

A further source of confusion is that the Condé in question is Condé-sur-l'Escaut, once a Flemish possession and now on the French-Belgian border, and not the more famous Château de Condé, which was a possession of the French royal family.

Condé-sur-l'Escaut was a secondary holding of the family d'Avesnes. The succession is discussed here (in French, but fairly easy to follow): http://fr.wikipedia.org/wiki/Liste_des_seigneurs_d%27Avesnes

Thanks for your reply Maven.
In his monography on Condé-sur-l'Escaut (1927), René Delame notes that he could not link Roger de Condé to any ancestor. His branch is certainly linked to Heribaud de Condé who was said to be the 1st lord of Condé branch called "Proprietary", thus not part of Avesnes one.
Will check your links.