Gwilym ap Gruffydd ap Heilen Lord of Penrhyn and Cwchwillan

   Other names for Gwilym were Gwilym ap Griffith and Gwilym ap Griffith ap Heilyn.

  Research Notes:

Cochwillan adjoins the Penrhyn estate.

Source: The History of the Princes, the Lords Marcher, and the Ancient Nobility of Powys Fadog, and the Ancient Lords of Arwystli, Cedewen, and Meirionydd by J. Y. W. Lloyd, Vol. IV, London, 1884, p. 341 "Gwilym ab Gruffydd, Lord of Penrhyn and Cwchwillan." This source swaps the wives of this Gwilym ab Gruffydd and Gruffydd ap Heilen (Gwen verch Ieuan ab Gruffydd vs. Efa verch Gruffydd ap David).

Which is correct??

Source: A Genealogical and Heraldic Dictionary of the Landed Gentry of Great Britain & Ireland" by John Burke & John Bernard Burke, vol. I, London, 1847, p. 736 has:

"The eldest son [of Heilin ap Tudor and Agnes verch Bloddyn], GRIFFITH AP HEILIN, was father of GWILYM AP GRIFFITH, living 26 EDWARD III., who m. Efa, dau. of Griffith ap David, of Cochwillan, eldest son of Tudor ap Madoc, Lord of Penrhyn, in Caernarvon, (who d. about 1284,) grandson of Yarddyr ap Cynddelw, Lord of Uchaf, and had two sons, 1. Bleddyn ap Gwilym... 2. Griffith ap Gwilym, of Penrhyn"

Source: Annals and Antiquities of the Counties and County Families of Wales by Thomas Nicholas, Vol. I, London, 1872, p. 362, "Gwilym ap Gruffydd, of Cochwillan, living 1353, m. Efa, dau. of Gruffydd ap Tudor of Cochwillan ap Tudor ap Madoc, Lord of Penrhyn, co. of Carnarvon, and grandson of Jarddur ap Cynddelw, Lord of Llechwedd-uchaf, great forester of Snoden, by whom he was father of two sons:-- 1. Gruffydd... 2. Bleddyn ap Gwilym..."

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From Welsh Biography Online (http://yba.llgc.org.uk/en/s1-GRIF-PEN-1300.html) :
"(1) GWILYM AP GRIFFITH AP HEILYN (third in descent from Tudur ab Ednyfed ), who d. c. 1370, m. (c. 1340) Eva, daughter of Griffith ap Tudur ap Madog ap Iarddur. Her father (d. c. 1310) and brother Gwilym ap Griffith of Llaniestyn, in Anglesey (d. c. 1375) were landowners of some note in Englefield and in various townships in Anglesey (Twrgarw, Penw and Caernarvonshire (Bodfeio). She was probably one of the co-heirs of her brother in 'Gafael Iarddur' in Bodfeio in 1352, and it was almost certainly this marriage which brought Cochwillan to her husband's family, together with a share of her family's lands in Anglesey. By her brother's will, dated 1375, her son, Griffith ap Gwilym (d. 1405 - see (2) below) inherited further lands in Anglesey and Caernarvonshire."

Gwilym married Eva verch Gruffydd ap David of Cwchwillan, daughter of Gruffydd ap David ap Tudor and Unknown, about 1340.

  Marriage Notes:

Source: Welsh Biography Online (http://yba.llgc.org.uk/en/s1-GRIF-PEN-1300.html)