Clydno Eiddin was a ruler in the Hen Ogledd

Hen Ogledd

Yr Hen Ogledd is a Welsh term used by scholars to refer to those parts of what is now northern England and southern Scotland in the years between 500 and the Viking invasions of c. 800, with particular interest in the Brythonic-speaking peoples who lived there.The term is derived from heroic...

, the Brythonic

Brythonic languages

The Brythonic or Brittonic languages form one of the two branches of the Insular Celtic language family, the other being Goidelic. The name Brythonic was derived by Welsh Celticist John Rhys from the Welsh word Brython, meaning an indigenous Briton as opposed to an Anglo-Saxon or Gael...

-speaking area in what is now Northern England

Northern England

Northern England, also known as the North of England, the North or the North Country, is a cultural region of England. It is not an official government region, but rather an informal amalgamation of counties. The southern extent of the region is roughly the River Trent, while the North is bordered...

 and southern Scotland

Scotland

Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...

 during the Early Middle Ages

Early Middle Ages

The Early Middle Ages was the period of European history lasting from the 5th century to approximately 1000. The Early Middle Ages followed the decline of the Western Roman Empire and preceded the High Middle Ages...

. "Eiddyn" is the Brythonic name for Edinburgh

Edinburgh

Edinburgh is the capital city of Scotland, the second largest city in Scotland, and the eighth most populous in the United Kingdom. The City of Edinburgh Council governs one of Scotland's 32 local government council areas. The council area includes urban Edinburgh and a rural area...

, implying a connection to that territory.

The Harleian genealogies

Harleian genealogies

The Harleian genealogies are a collection of Old Welsh genealogies preserved in British Library, Harleian MS 3859. Part of the Harleian Collection, the manuscript, which also contains the Annales Cambriae and a version of the Historia Brittonum, has been dated to c. 1100, although a date of c.1200...

 give Clydno's pedigree. He is said to be the son of a certain Cinbelim or Cynfelyn, the son of Dumnagual Hen

Dumnagual I of Alt Clut

Dumnagual I, also known as Dumnagual Hen , was a ruler of the Brythonic kingdom of Alt Clut , later known as Strathclyde, probably sometime in the early 6th century. His biography is vague, but he was regarded as an important ancestor figure for several kingly lines in the Hen Ogledd or "Old North"...

, an early ruler of Alt Clut

Kingdom of Strathclyde

Strathclyde , originally Brythonic Ystrad Clud, was one of the early medieval kingdoms of the celtic people called the Britons in the Hen Ogledd, the Brythonic-speaking parts of what is now southern Scotland and northern England. The kingdom developed during the post-Roman period...

 (later known as Strathclyde). The later genealogy Bonedd Gwŷr y Gogledd

Bonedd Gwŷr y Gogledd

Bonedd Gwŷr y Gogledd is a brief Middle Welsh tract which claims to give the pedigrees of twenty 6th-century rulers of the Hen Ogledd , the Brythonic-speaking parts of southern Scotland and northern England. It is attested in a number of manuscripts, the earliest being NLW, Peniarth MS 45, which...

gives an altered version of this genealogy; here Cynfelyn is Clydno's grandfather, and the family is attached to the line of the ancestor figure Coel Hen.

An attack by Clydno and several other northern rulers on Gwynedd

Kingdom of Gwynedd

Gwynedd was one petty kingdom of several Welsh successor states which emerged in 5th-century post-Roman Britain in the Early Middle Ages, and later evolved into a principality during the High Middle Ages. It was based on the former Brythonic tribal lands of the Ordovices, Gangani, and the...

 in North Wales

North Wales

North Wales is the northernmost unofficial region of Wales. It is bordered to the south by the counties of Ceredigion and Powys in Mid Wales and to the east by the counties of Shropshire in the West Midlands and Cheshire in North West England...

 is recounted in the Gwynedd version of the Welsh laws preserved in the Book of Chirk. According to the story, after Elidir Mwynfawr, a prince of the North, had been slain in Gwynedd, Clydno joined with Rhydderch Hael

Riderch I of Alt Clut

Riderch I , commonly known as Riderch or Rhydderch Hael , was a ruler of Alt Clut and the greater region later known as Strathclyde, a Brittonic kingdom that existed on the valley of the River Clyde in Scotland during the British Sub-Roman period...

 and two other kings called Nudd Hael and Mordaf Hael to avenge him. They proceeded to raid and burn Arfon

Cantref Arfon

The mediaeval Welsh cantref of Arfon in north-west Wales was the core of the Kingdom of Gwynedd. Later it was included in the new county of Caernarfonshire, together with Llŷn and Arllechwedd under the terms of the Statute of Rhuddlan in 1284...

 until Rhun ap Maelgwn and the armies of Gwynedd forced them out.

Clydno's name also appears in lists of the Thirteen Treasures of the Island of Britain

Thirteen Treasures of the Island of Britain

The Thirteen Treasures of the Island of Britain are a series of items in late medieval Welsh tradition. Lists of the items appear in texts dating to the 15th and 16th centuries...

. According to these lists, Clydno possessed a magical halter

Halter

A halter, headcollar, or, less often, headstall, is headgear that is used to lead or tie up livestock and, occasionally, other animals; it fits behind the ears , and around the muzzle. To handle the animal, usually a lead rope or lead shank is attached...

, the Cebystr Clydno Eiddin. The explanatory note attached to later versions of the lists explain the halter's property: when he affixed it to a staple at the foot of his bed, he would find whatever horse he wished in it.

Clydno's son Cynon was also a figure of Welsh tradition. The poem Y Gododdin

Y Gododdin

Y Gododdin is a medieval Welsh poem consisting of a series of elegies to the men of the Britonnic kingdom of Gododdin and its allies who, according to the conventional interpretation, died fighting the Angles of Deira and Bernicia at a place named Catraeth...

names him as one of the Britons who fought against the Angles

Angles

The Angles is a modern English term for a Germanic people who took their name from the ancestral cultural region of Angeln, a district located in Schleswig-Holstein, Germany...

 at the disastrous Battle of Catraeth; at one point the poem identifies him as the only survivor. Later works mention Cynon's great love for Morvydd

Morvydd

Morfydd ferch Urien is a figure of Welsh Arthurian legend. She is the daughter of Urien Rheged by Modron, and twin sister to Owain. Morfydd appears in the Welsh Triads and is also referred to in Culhwch and Olwen...

, daughter of Urien Rheged, and he appears in the prose tale Owain, or the Lady of the Fountain, taking the role given to Calogrenant

Calogrenant

Sir Calogrenant, sometimes known in English as Colgrevance, or, in ancient Welsh, Cynan ap Clydno, is a Knight of the Round Table in Arthurian legend. He is a cousin to Sir Ywain, and his courtesy and eloquence were known throughout the kingdom....

in other versions of the story.