Price of Esgairweddan family were the descendants of Dafydd the illegitimate son of Dafydd ap Llywelyn, Prince of Wales and King of Gwynedd between 1240-1246. He is the ancestor of the royal Prys or Price Family of Esgairweddan who bore the royal arms of Gwynedd as their own. It is generally considered that this family, in the male line, died out on the death of Robert Price of Esgairweddan in 1702.

Their claim is attested in Pedigrees of the Three Counties of North Wales above Conway by Lewys Dwnn, Deputy Herald, which was published in 1588 in the thirtieth year of the reign of Elizabeth I. The original hand written manuscript was copied and printed in 1846 by Sir Samuel Rush Meyrick.

Dafydd ap Dafydd ap Llywelyn was presumably a minor when his father, the prince, died in 1246 and was unable to contest the throne of Gwynedd which was then claimed by Owain ap Gruffydd and Llywelyn ap Gruffydd who were his cousins. His mother is not known. If Dafydd was conceived in 1239 just prior to his fathers elevation to the throne then he would have been seven at the time of his fathers death in 1246.

In 1588 the pedigree of Rhys ab Ieuan ap Dafydd ap Gruffydd ap Dafydd ap Ithel ap Dafydd ap Llowhir Vychan ap Llowhir ap Ieuan ap Dafydd ap Dafydd ap Llywelyn Mawr ap Iorwerth Drwyndwn ap Owain Gwynedd ap Gruffydd ap Cynan tywysog talaith Aberffraw was attested by William Hughes and John Davies in the aforementioned publication by Lewis Dwnn. In 1588 Edward (Prys) ap Rhys ab Ieuan ap Dafydd had four sons who bore the surname Prys (ap Rhys) which was later transmuted into the Welsh surname Price.

According to Old & Extinct Families of Meirionyddshire the last known heir male, Robert Price, died in 1702. Any proven extant heirs male of this family would still be entitled to bear the Royal Arms of Gwynedd and as such would be de jure heirs to the long dormant throne of Gwynedd.

References

Dwnn, Lewys; Heraldic Visitations of North Wales and Part of the Marches, Volume II, page 240 (plate CLXXII) as attested by William ap Dafydd Lloyd, August 2nd 1588. The original manuscript was copied by William Hughes and John Davies for publication by Sir Samuel Rush Meyrick in 1846. This work was reprinted by Bridge Books 2005 (ISBN 1-84494-016-0).