Ieuan ap Gruffudd Foel

See Peter Bartrum, https://cadair.aber.ac.uk/dspace/bitstream/handle/2160/4808/cadwgon... (February 12, 2020; Anne Brannen, curator)

Please see Darrell Wolcott: Bartrum's "Pedigrees of the Welsh Tribal Patriarchs"' # 4 Cadwgan Fantach; http://www.ancientwalesstudies.org/id172.html. (Steven Ferry, September 7, 2019.)

Please see Darrell Wolcott: Sorting Out the Gwaithfoeds; http://www.ancientwalesstudies.org/id125.html. (Steven Ferry, September 5, 2020.)

Please see Darrell Wolcott: Rhydderch Ddu of Tal-y-Llyn; http://www.ancientwalesstudies.org/id314.html (Steven Ferry, April 9, 2023.)