House of Aberffraw in the context of "Wales in the late Middle Ages"

Wales in the late Middle Ages spanned the years 1282–1542, beginning with conquest and ending in union. Those years covered the period involving the closure of Welsh medieval royal houses during the late 13th century, and Wales' final ruler of the House of Aberffraw, the Welsh Prince Llywelyn II, also the era of the House of Plantagenet from England, specifically the male line descendants of Geoffrey Plantagenet, Count of Anjou as an ancestor of one of the Angevin kings of England who would go on to form the House of Tudor from England and Wales.

The House of Tudor would go on to create new borders by incorporating Wales into the Kingdom of England by the Laws in Wales Acts 1535–1542, effectively ever since then new shires had been created in place of castles, by changing the geographical borders of the Kingdoms of Wales to create a new definitions for towns and their surrounding lands. Historians referring to the end of the late Middle Ages in Britain often reference the Battle of Bosworth Field involving Henry VII of England, which began a new era in Wales.

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).

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.

The Principality of Wales (Welsh: Tywysogaeth Cymru) was originally the territory of the native Welsh princes of the House of Aberffraw from 1216 to 1283, encompassing two-thirds of modern Wales during its height of 1267–1277. Following the conquest of Wales by Edward I of England of 1277 to 1283, those parts of Wales retained under the direct control of the English crown, principally in the north and west of the country, were re-constituted as a new Principality of Wales and ruled either by the monarch or the monarch's heir though not formally incorporated into the Kingdom of England. This was ultimately accomplished with the Laws in Wales Acts 1535–1542 when the Principality ceased to exist as a separate entity.

The Principality was formally founded in 1216 by native Welshman and King of Gwynedd, Llywelyn the Great who gathered other leaders of pura Wallia at the Council of Aberdyfi. The agreement was later recognised by the 1218 Treaty of Worcester between Llywelyn the Great of Wales and Henry III of England. The treaty gave substance to the political reality of 13th-century Wales and England, and the relationship of the former with the Angevin Empire. The principality retained a great degree of autonomy, characterized by a separate legal jurisprudence based on the well-established laws of Cyfraith Hywel, and by the increasingly sophisticated court of the House of Aberffraw. Although it owed fealty to the Angevin king of England, the principality was de facto independent, with a similar status in the empire to the Kingdom of Scotland. Its existence has been seen as proof that all the elements necessary for the growth of Welsh statehood were in place.

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.