Wynn's work
The History of the Gwydir Family, which had a great reputation in North Wales, was intended to assert his claim to royal ancestry. In a legal challenge to this claim, Thomas Prys of Plas Iolyn brought a case against him and Sir John was forced to defend himself in court. He won the case and afterwards was recognised as the most prominent male heir of the
House of Gwynedd. Under Welsh succession law the head of the Price of Esgairweddan family at the time, descended through
Iorwerth ab Owain Gwynedd and
Dafydd II, would lead the senior line and be
de jure Princes of Gwynedd, however they died out in the male line in 1702 and the royal title and headship of the House of Aberffraw would have passed then from the Price family to the Wynn Family of Gwydir at that time under the native succession law of Kings laid out in Cyfraith Hywel as descendants of one of the surviving senior lineages of the Welsh Royal Houses. John Wynn's book was first published by Daines Barrington in 1770, and in 1878 an edition was published at
Oswestry. It is valuable as the only work which describes the state of society in North Wales in the 15th and the earlier part of the 16th century. •
Owain Gwynedd, Prince of Gwynedd (d. November 1170), married Cristina ferch Gronw ap Owain ap Edwin •
Rhodri ab Owain Gwynedd, Lord of Anglesey (d.1195), married Annest ferch Rhys ap Gruffudd • Tomas ap Rhodri married Annest ferch Einion ap Seisyllt • Caradog ap Tomas, married Efa ferch Gwyn ap Gruffudd ap Beli • Gruffudd ap Caradog, married Lleuca ferch Llywarch Fychan ap Llywarch • Dafydd ap Gruffudd of Rhos, married Efa ferch Gruffudd Fychan • Hywel ap Dafydd, married Efa ferch Evan ap Hywel ap Maredudd • Maredudd ap Hywell (d. after 1353), married Morfydd verch Ieuan ap Dafydd ap Trahaern Goch • Ifan ap Robert (b. 1438, d. 1469), married Catherine ferch Rhys ap Hywel Fychan •
Maredudd ap Ifan (Ieuan) ap Robert (b. c. 1459, d. 18 March 1525), married Ales ferch William Gruffudd ap Robin •
John "Wynn" ap Maredudd (d. 9 July 1559), married Ellen Lloyd ferch Morys ap John •
Morys Wynn ap John (d.1580), married (1) Jane Bulkeley; (2) Ann Grevill; and (3) Katherine of Berain • Sir John Wynn ap Morys of Gwydir, later Sir John Wynn, 1st Baronet ==Legacy==