What are de fiennes?

Some articles on de fiennes, fiennes, de:

Blanche De Brienne, Baroness Tingry - Marriage and Issue
... In the year 1269, Blanche married William II de Fiennes, Baron of Tingry and Fiennes, son of Enguerrand II de Fiennes and Isabelle de Conde ... William and Blanche had at least one son and two daughters Jean de Fiennes, Seigneur of Fiennes and Tingry (b ... before 1281 in France – 1340), in 1307 married Isabelle de Dampierre, daughter of Guy de Dampierre, Count of Flanders and Isabelle of Luxembourg ...
Margaret Mortimer, Baroness Wigmore
... Margaret Mortimer, Baroness Mortimer (née de Fiennes after 1269 – 7 February 1333), was an English noblewoman born to William II de Fiennes, Baron Tingry and Blanche de Brienne ... Her paternal grandparents were Enguerrand II de Fiennes and Isabelle de Conde ... Her maternal grandparents were Jean de Brienne and Jeanne, Dame de Chateaudun ...