I'm currently trying to find the link in my wife's familiy to Sir John Rhys (formerly Rees). In the early 1900s, her grandmother, Mary Jane Jenkins, was told by the chapel minister that she was related to Sir John. Mary Jane's mother was Elisabeth Rees (1876 - 1960) & her father was Thomas Rees (1821 - 1899).
I know that Thomas's father was Hugh Rees, who died at Sgybor y Coed in 1861, but as yet I cannot find the link with Sir John's family. although they were clearly part of the same Rees family of the Fwrnais, Talybont, Nant y Moch, Ponterwyd area.
Sir John had an elder sister, margaret, who was ~9 years old when Sir John was born. In the 1841 census, the family is incorrectly transcribed onto the Ancestry.com search engine as "Rus": Hugh Rus, Jane Rus, Margaret Rus & John Rus.
John's parents, Hugh Rees & Jane Mazon were married in 1837. We have the marriage certificate showing that Hugh was born ~1809 & his father is recorded as David Rees, farmer. We also have birth certificates of John & his siblings, showing that Hugh was an agricultural labourer, a farmer & at one point a lead-miner.