Tegwared y Bais Wen ap Llywelyn (English: Tegwared with the White Mantle, son of Llewelyn), Lord of Trefdraeth was a natural son of Llywelyn the Great, Prince of Aberffraw, by a woman in some sources given as Crysten. He was born circa 1210. 'The white mantle' refers to his coat of arms (as shown to the right).
His descendants are one of the few surviving male-line descendants of Llywelyn. Tegwared was not formally recognised as part of the House of Aberffraw by the English king, even though his father was the head, due to his illegitimacy. As such, upon the extinction of Llywelyn's legitimate male-line, the theoretical position of the head of the House of Aberffraw returned to a descendant of Owain Gwynedd, today widely considered to be the Anwyl family. This is complicated, however, by the fact that Llywelyn was the first Welsh king to be formally recognised by the English and signed the Treaty of Worcester in 1218, by which only his legitimate male-line descendants could succeed him. This was contrary to Hywel Dda's laws that illegitimate children had an equal right of succession, so it is disputed by genealogists who the head of the house and therefore pretender to the Prince of Wales would be. Tegwared served as a General in his father's army and held the Lordship of Trefdraeth, Anglesey, where his posterity lived for the next 600 years.
It is recorded that he was adopted and raised by Ednyfed Vychan from whom the Tudurs were descended, his father's Seneschal - an office comparable to a sort of hereditary Prime Minister today. Tegwared later married his daughter, Gwenlian ferch Ednyfed Vychan. They had the following children:Howel ap Tegwared
Angharad ap Tegwared
Arddun ap Tegwared
Tegwared Vychan ap Tegwared (b. circa 1250)