‌William III 5Th Baron De and Maud (Matilda) De were married in a religious ceremony in 1169 in England.  They had thirteen sons and seven daughters, named Roger De, Robert De, Thomas De, Giles De, William IV The Younger De, Walter De, Reginald De, Hugh De, Henry De, Bernard De, Fulk De, Phlilp De, John De, Flandrina De, Matilda De, Joan De, Laurette De, Margaret De, Leuca De and Eleanor De.