List of rulers of Gwynedd in the context of "Cadwaladr"

Gruffudd ap Llywelyn (c. 1010 – 5 August 1063) was the only Welsh king to unite all of Wales, ruling from 1055 to 1063. He had previously been King of Gwynedd and Powys from 1039 to 1055. Gruffudd was the son of Llywelyn ap Seisyll, King of Gwynedd, and Angharad, daughter of Maredudd ab Owain, King of Deheubarth, and the great-great-grandson of Hywel Dda. After his death, Wales was again divided into separate kingdoms.

Cadwallon ap Cadfan (died 634) was the King of Gwynedd from around 625 until his death in battle. The son and successor of Cadfan ap Iago, he is best remembered as the King of the Britons who invaded and conquered Northumbria, defeating and killing its king, Edwin, prior to his own death in battle against Oswald of Bernicia. His conquest of Northumbria, which he held for a year or two after Edwin died, made him one of the last recorded Celtic Britons to hold substantial territory in eastern Britain until the rise of the Welsh House of Tudor. He was thereafter remembered as a national hero by the Britons and as a tyrant by the Anglo-Saxons of Northumbria. Uniquely among seventh-century Welsh monarchs, Cadwallon also has three poems associated with him, which may be contemporaneous to his lifetime.

Gruffudd ap Cynan (c. 1055–1137) was King of Gwynedd from 1081 until his death in 1137. In the course of a long and eventful life, he became a key figure in Welsh resistance to Norman rule.

As a descendant of Rhodri Mawr (Rhodri the Great), Gruffudd ap Cynan was a senior member of the princely House of Aberffraw. Through his mother, Gruffudd had close family connections with the Norse settlement around Dublin and he frequently used Ireland as a refuge and as a source of troops. He three times gained the throne of Gwynedd and then lost it again, before regaining it once more in 1099 and this time keeping power until his death. Gruffudd laid the foundations which were built upon by his son Owain Gwynedd and his great-grandson Llywelyn ab Iorwerth (Llywelyn the Great).

Llywelyn ap Seisyll (died 1023) was a king of Gwynedd in the 11th century who ruled over the Welsh kingdoms of Gwynedd, Powys and Deheubarth.

Llywelyn ap Gruffudd (d. 11 December 1282), also known as Llywelyn II and Llywelyn the Last (Welsh: Llywelyn Ein Llyw Olaf, lit. 'Llywelyn, our last leader'), was Prince of Gwynedd, and later was recognised as the Prince of Wales (Latin: Princeps Walliae; Welsh: Tywysog Cymru) from 1258 until his death at Cilmeri in 1282. Llywelyn was the son of Gruffudd ap Llywelyn ap Iorwerth and grandson of Llywelyn ab Iorwerth (also known as Llywelyn the Great, or Llywelyn I), and he was one of the last native and independent princes of Wales before its conquest by Edward I of England and English rule in Wales that followed, until Owain Glyndŵr held the title during his rebellion of 1400–1415.

The Kingdom of Gwynedd was a Welsh kingdom which first appeared at the turn of the sixth century. Based in northwest Wales, the rulers of Gwynedd repeatedly rose to dominance and were acclaimed as "King of the Britons" before losing their power in civil wars or invasions. The kingdom of Gruffudd ap Llywelyn—the King of Wales from 1055 to 1063—was shattered by a Saxon invasion in 1063 just prior to the Norman invasion of Wales, but the House of Aberffraw restored by Gruffudd ap Cynan slowly recovered and Llywelyn the Great of Gwynedd was able to proclaim the Principality of Wales at the Aberdyfi gathering of Welsh princes in 1216. In 1277, the Treaty of Aberconwy between Edward I of England and Llywelyn's grandson Llywelyn ap Gruffudd granted peace between the two but would also guarantee that Welsh self-rule would end upon Llywelyn's death, and so it represented the completion of the first stage of the conquest of Wales by Edward I.

Welsh tradition credited the founding of Gwynedd to the Brittonic polity of Gododdin (Old Welsh Guotodin, earlier Brittonic form Votadini) from Lothian invading the lands of the Brittonic polities of the Deceangli, Ordovices, and Gangani in the 5th century. The sons of their leader, Cunedda, were said to have possessed the land between the rivers Dee and Teifi. The true borders of the realm varied over time, but Gwynedd proper was generally thought to comprise the cantrefs of Aberffraw, Cemais, and Cantref Rhosyr on Anglesey and Arllechwedd, Arfon, Dunoding, Dyffryn Clwyd, Llŷn, Rhos, Rhufoniog, and Tegeingl at the mountainous mainland region of Snowdonia opposite.

Idwal Foel (Idwal the Bald) (died c. 942) or Idwal ab Anarawd (Idwal son of Anarawd) was a 10th-century King of Gwynedd in Wales. A member of the House of Aberffraw, he inherited the throne from his father, Anarawd ap Rhodri. William of Malmesbury credited him as "King of the Britons" in the manner of his father.

Eleanor de Montfort, Princess of Wales and Lady of Snowdon (1252 – 19 June 1282) was an English noblewoman and Welsh princess through her marriage to Llywelyn ap Gruffudd, who was Prince of Gwynedd, and later, Prince of Wales. She was the daughter of Simon de Montfort, 6th Earl of Leicester and Eleanor of England. She was also the second woman who can be shown to have used the title Princess of Wales.