Jean III De Pierrepont
Jean III was born about 1240.  He died in 1282.

 Isabelle De Mercoeur
Isabelle was born about 1240.

 Jean IV De Pierrepont
Jean IV was born in 1260.  He died at the age of 44 on August 18th, 1304 in , Mons-En-Pévèle, 59,.  He was buried in , Val-Lès-Ray, 70,.