Gwladus Ddu, ("Gwladus the Dark"), full name Gwladus ferch Llywelyn (died 1251) was a Welsh noblewoman who was a daughter of Llywelyn the Great of Gwynedd and was to be married to two Marcher lords. 
   Sources differ as to whether Gwladus was Llywelyn's legitimate daughter by his wife Joan or an illegitimate daughter by Tangwystl Goch. Some sources[who?] say that Joan gave her lands to Gwladus, which suggests, but does not prove, the former. Gwladus is recorded in Brut y Tywysogion as having died at Windsor in 1251.     
  Marriage 
 She first married Reginald de Braose, Lord of Brecon and Abergavenny in about 1215, but they are not known to have had any children. After Reginald's death in 1228 she was probably the sister recorded as accompanying Dafydd ap Llywelyn to London in 1229.  
 She then married Ralph de Mortimer of Wigmore about 1230. Ralph died in 1246, and their son, Roger de Mortimer, inherited the Lordship.    
  Issue 
 Roger Mortimer, 1st Baron Wigmore Married Maud de Braose.  
 Hugh de Mortimer  
 John de Mortimer  
 Peter de Mortimer    
  References 
 Ancestral Roots of Certain American Colonists Who Came to America Before 1700 by Frederick Lewis Weis; Lines 132-C-29, 176B-28  
 John Edward Lloyd (1911) A history of Wales from the earliest times to the Edwardian conquest (Longmans, Green & Co.)    
 Source:  
http://en.wikipedia.org/wiki/Gwladus_Ddu