Rhodri Mawr

Origins

Rhodri was the son of Merfyn Frych, King of Gwynedd, whose death the Welsh annals record in 844. Documented: Annales Cambriae The genealogical tradition names his mother as Nest of the royal house of Powys. Genealogies

A medieval poem, Cyfoesi Myrddin a Gwenddydd ei Chwaer, describes Merfyn as coming “from the land of Manaw”. Tradition: Cyfoesi Myrddin a Gwenddydd ei Chwaer This has been interpreted as a connection to the Isle of Man, although Manaw Gododdin in northern Britain has also been proposed. Merfyn’s precise origins remain uncertain. Inferred: J. E. Lloyd, “Merfyn Frych”, Dictionary of National Biography

Rhodri’s date of birth is not known.

Building a kingdom

Rhodri succeeded his father as king of Gwynedd in 844. Documented: Thomas Jones Pierce, “Rhodri Mawr”, Dictionary of Welsh Biography

His authority later extended into Powys. The conventional account places his acquisition of the kingdom in 855, following the death of its king, Cyngen. Precisely how Rhodri secured control is uncertain; it should not be treated as a straightforward inheritance through his mother’s family. Inferred: Thomas Jones Pierce, “Rhodri Mawr”, Dictionary of Welsh Biography

Around 872, Gwgon, ruler of Seisyllwg, drowned. The Annales Cambriae records his death under 871 in the linked translation, calling him king of Ceredigion. Documented: Annales Cambriae, entry labelled 871

Rhodri’s wife, Angharad, is identified as Gwgon’s sister. Genealogies Following Gwgon’s death, Seisyllwg, comprising Ceredigion and Ystrad Tywi, came under Rhodri’s authority. The family connection helps explain the traditional account of this expansion, but the annal does not describe how control passed to him. Inferred: Thomas Jones Pierce, “Rhodri Mawr”, Dictionary of Welsh Biography

Against the Vikings

In 856 Rhodri killed the Viking leader Horm. The Annals of Ulster records that “Horm, chief of the dark foreigners, was killed by Rhodri son of Mervyn, king of Wales”. Documented: Annals of Ulster, U856.6

The victory may also have found an echo on the Continent. Historian Nora Chadwick discusses two poems by the Irish scholar Sedulius Scottus: one praising a ruler called “Roricus”, identified with Rhodri, and another celebrating a victory over the Norsemen. Their connection with Rhodri and the events of 856 is an interpretation rather than an explicit statement in the poems. Inferred: Nora Chadwick, Celtic Britain (1963), chapter IV

The Last Years

Rhodri’s final years brought renewed Viking pressure. The Annales Cambriae records a battle on Anglesey, known as the “battle of Sunday”, under 876 in the linked translation, but gives no details of its participants or outcome. Documented: Annales Cambriae, entry labelled 876

In 877 Rhodri fled to Ireland. The Annals of Ulster states that “Rhodri son of Merfyn, king of the Britons, came in flight from the dark foreigners to Ireland”. It does not explicitly connect his flight with the Anglesey battle. Documented: Annals of Ulster, U877.3

Rhodri subsequently returned to Britain. In 878 he and his son Gwriad were killed by the English, described in the Annales Cambriae as “the Saxons”. Documented: Annales Cambriae, entry labelled 877 in the linked translation; dated 878 by J. E. Lloyd Lloyd identifies the attackers as Mercians. Documented: J. E. Lloyd, “Anarawd ap Rhodri”, Dictionary of Welsh Biography

In 881 the Mercians were defeated at Conwy, a victory Lloyd attributes to Rhodri’s son Anarawd. Documented: J. E. Lloyd, “Anarawd ap Rhodri”, Dictionary of Welsh Biography The Welsh annal describes the battle as “Vengeance for Rhodri at God's hand”. Documented: Annales Cambriae, entry labelled 880 in the linked translation

His Sons and the Royal Houses of Wales

Rhodri’s descendants became central to the history of medieval Wales. Asser’s Life of King Alfred, written in 893, describes Anarawd and an unnamed brother abandoning their Northumbrian alliance and submitting to Alfred. Documented: Asser, Life of King Alfred, chapter 80

• Anarawd: succeeded Rhodri in Gwynedd. His descendants included Llywelyn the Great and Llywelyn ap Gruffudd. Genealogies
• Cadell: father of Hywel Dda, traditionally remembered as the great Welsh lawgiver. His descendants formed the ruling dynasty of Deheubarth. Genealogies
• Merfyn: traditionally associated with the rule of Powys. Tradition
• Gwriad: killed alongside Rhodri by the English in 878. Documented: Annales Cambriae, entry labelled 877 in the linked translation; dated 878 by J. E. Lloyd

The dynasties descended from Anarawd and Cadell are commonly known as the houses of Aberffraw and Dinefwr, after the royal seats associated with Gwynedd and Deheubarth.

Writing in the late twelfth century, Gerald of Wales describes Rhodri dividing his territory between three sons: Merfyn, Anarawd and Cadell. His account is a later tradition, not contemporary evidence for how the succession took place. Tradition: Gerald of Wales, Description of Wales, Book I, chapter 2

Aberffraw and Dinefwr were royal seats associated with Gwynedd and Deheubarth. Gerald names them in the same work, but this does not establish when their names came to be used as labels for the dynasties. Documented: Gerald of Wales, Description of Wales, Book I, chapter 4

Why “Mawr”?

Mawr means “great”. Gerald of Wales uses the name “Rhodri Mawr”, or “Roderic the Great”, in his Description of Wales, written centuries after Rhodri’s lifetime. Documented: Gerald of Wales, Description of Wales, Book I, chapter 2

The name expresses the reputation Rhodri acquired in Welsh historical tradition. Exactly when it first came into use, and whether anyone called him “Mawr” during his lifetime, remains uncertain.

Timeline

1. 844 Death of Merfyn Frych; Rhodri becomes King of Gwynedd.
2. 854/5 Cyngen of Powys dies in Rome; Powys passes to Rhodri.
3. 856 Rhodri kills the Danish leader Horm.
4. c. 872 Gwgon of Seisyllwg drowns; Seisyllwg comes under Rhodri.
5. 877 Defeat by the Danes on Anglesey; Rhodri flees to Ireland.
6. 878 Rhodri and his son Gwriad are killed by the English.
7. 881 Anarawd defeats the Mercians at Conwy, “vengeance for Rhodri”.

Documented or traditional?

Throughout this site, statements are tagged to show how we know them:

Documented

Recorded in a medieval annal or chronicle, usually written within living memory or copied from such a record.

Genealogies

Found in the medieval Welsh pedigrees, compiled later. Often reliable for close relationships, less so further back.

Tradition

Told in later medieval writing or tradition, without an early record behind it.

Inferred

A conclusion historians draw from the records, rather than something the records state.

Sources and Further Reading

Annals and Medieval Accounts

• Annales Cambriae (Annals of Wales), English translation, for Merfyn’s death, Gwgon’s drowning, Rhodri and Gwriad’s deaths, and the battle of Conwy. Some year labels differ from the dates used in this article.
• Annals of Ulster, English translation, University College Cork, particularly U856.6, recording Horm’s death, and U877.3, recording Rhodri’s flight to Ireland.
• Asser, Life of King Alfred, translated by Albert S. Cook, chapter 80, for Anarawd’s Northumbrian alliance and submission to Alfred.
• Gerald of Wales, The Description of Wales, Book I, chapters 2–4, for the later account of Rhodri’s division of his territory, princely genealogies and royal seats.

Historical Studies

• Thomas Jones Pierce, “Rhodri Mawr”, Dictionary of Welsh Biography, an overview of Rhodri’s reign and territorial expansion. This entry dates his death to 877 rather than 878.
• Thomas Jones Pierce, “Merfyn Frych”, Dictionary of Welsh Biography, for Rhodri’s father and the proposed Manx connection.
• J. E. Lloyd, “Anarawd ap Rhodri”, Dictionary of Welsh Biography, for the succession after Rhodri’s death and the victory at Conwy.
• J. E. Lloyd, “Merfyn Frych”, Dictionary of National Biography (1894), for the poetic reference to Manaw and its possible interpretations.
• Nora Chadwick, Celtic Britain (1963), chapter IV, for the proposed connection between Rhodri’s Viking victory and the poetry of Sedulius Scottus.