The period from 800-1000 AD is an important period in the history of Wales, in as much as the constant threat and tension created by the presence of powerful Anglo-Saxon kingdoms to the east helped define and create a sense of separate identity and even nationalism - though that nationalism was often overshadowed by regional interests.

Numerous attempts were made throughout this period to create, if not a nation of Wales, then at least larger and more powerful kingdoms within Wales. One of the early leaders of these tentative movements toward nationalism was Rhodri ap Merfyn, later to be known as Rhodri Mawr (Rhodri the Great).

Rhodri Mawr brought the kingdoms of Gwynedd, Powys and Seisyllwg under his control, and fought the threats of the Anglo Saxons and Vikings. Rhodri Mawr was the first ruler of Wales to be given the epithet 'Mawr' or 'The Great', reflecting both his territory and his military achievements.

He was the son of Merfyn Frych ap Gwriad, king of Gwynedd and Nest ferch Cadell of the royal house of Powys. He inherited his father's kingdom in 844, and when Nest's brother Cyngen ap Cadell died, Powys passed to Rhodri's control.

His marriage to Angharad, the sister of Gwgon, king of Seiswllwg became very beneficial when Gwgon drowned. Another kingdom was handed on a plate to Rhodri.

He is called "King of the Britons" by the 'Annals of Ulster'. In some later histories, he is referred to as "King of Wales", although the title is anachronistic and his realm did not include southern Wales.

He regularly was forced to defend his territory, both against the Anglo Saxons across the border and the marauding Scandinavians. Rhodri Mawr is thought to have built the first fort at Dinefwr Castle.

In 856, Rhodri fought the Danes and won a famous victory. The Chronicle of the Princes records two victories by Rhodri in 872: the first at a place given variously as Bangolau, Bann Guolou or Bannoleu, where he defeated the Vikings in Anglesey "in a hard battle" and the second at Manegid or Enegyd where the Vikings "were destroyed". Alas, he is thought to have been killed, in battle, by the Anglo Saxons of Mercia in 878.

His son Anarawd ap Rhodri continued to rule the combined Powys and Gwynedd kingdoms.

Native Princes of Gwynedd / Wales
Monarch	Birth	Reign
Rhodri Mawr	circa 820-878
Hywel Dda	circa 880 - 950
Grufydd ap Llywelyn	circa 1007-1063
Grufydd ap Cynan	circa 1055 - 1137
Owain Gwynedd	circa 1080	1137-1170
Llywelyn Fawr  (the Great) - Llywelyn ap Iorwerth	1173	1199-1240
Dafydd ap Llywelyn	1212	1240-1246
Llywelyn Ein Llyw Olaf  (the Last)  - Llywelyn ap Gruffydd	circa 1223	1246-1282
Owain Glyndwr	circa 1349	1400 - 1404

Sources:
http://www.bbc.co.uk/
http://www.britainexpress.com