(c. 1223 – 1282)
From Encyclopedia of Heraldry by John Burke and John Bernard Burke (1844)
Blazon: Per quarterly or and gules four lions passant guardant counterchanged
Llywelyn ap Gruffudd was the great-great-grandson of Owain ap Gruffudd, and the last sovereign prince of Wales. Just to give you an idea of the… lack of priority the Burkes give to fact-checking, they give Llywelyn’s date of death as 1272 – one decade earlier than he actually died, at the Battle of Orewein Bridge. Orewein Bridge marked the final victory of Edward I over the Welsh, and the effective end of Welsh independence.
This is actually not as unfounded as the other arms of the Welsh tribes. Llewelyn lived right about the time that we start seeing evidence of the use of heraldry in Wales, so it’s not out of the question that he might have used arms. I can’t find any solid evidence that he used these arms, but they’ve developed a pretty strong association with the Kingdom of Gwynedd and Wales in general. There’s evidence (actual evidence!) that Owain Glyndŵr (c. 1359 – c. 1415) used the very similar per quarterly or and gules, four lions rampant counterchanged. Since 1911, the arms of the Prince of Wales have used the arms the Burkes attribute to Llywelyn as an escutcheon of pretense. Moreover, the arms of the Gwynedd County Council, until 1996, had a chief party of three, I and III or a lion passant guardant gules armed and langued azure, II gules a lion rampant or.