Principality of Cumbria

Regnum Cumbrorum — The Kingdom of the Cumbrians

Overview

The Principality of Cumbria, known in Latin as Regnum Cumbrorum, was the great Brittonic kingdom of the northwest. It stretched from the River Clyde in Scotland south across the Solway into the valleys of modern Cumberland. Its people, the Cumbrians (Cymry), spoke Cumbric, a Celtic language related to Old Welsh, and considered themselves kin to the Welsh of the south.

At the very heart of this realm lay the Ennerdale Valley — later known as the Bailiwick of Ennerdale. Situated in the western fells, Ennerdale commanded access between the Solway, the Irish Sea, and the inner mountain passes. This made it not only a strategic crossing point but also a symbolic epicenter of Cumbrian identity and governance.

Chronology

• 5th–7th centuries — Alt Clut
  The early Brittonic kingdom centered on Dumbarton Rock (Alt Clut = “Rock of the Clyde”). Cumbric-speaking peoples also occupied the western valleys of present-day Cumbria, with Ennerdale forming a natural bastion.

• 8th–9th centuries — Pressures and Viking Raids
  Viking incursions culminated in the sack of Dumbarton in 870. Surviving royal lines and Cumbrian communities maintained power further south, with the Solway and western valleys — including Ennerdale — becoming more central to the polity’s continuity.

• 9th–10th centuries — Strathclyde / Ystrad Clud
  The realm became known as Strathclyde, but Latin chronicles called it Regnum Cumbrorum. Ennerdale and the Cumbrian valleys represented the frontier zone where Scottish, Norse, and English spheres met, serving as the living heart of the Cumbrian principality.

• c. 1000–1030 — Scottish Overlordship
  Under Malcolm II of Alba, Strathclyde came under Scottish overlordship. The Cumbrian valleys remained distinctive; Ennerdale was remembered as a bailiwick and liberty in its own right, embodying continuity of local governance even under outside rule.

• 1113–1124 — Prince of the Cumbria or Cumbrians
  David, brother of Alexander I of Scotland, ruled Cumbria as Princeps Cumbrorum. His base at Carlisle extended authority into the western fells. Ennerdale, as a bailiwick, was the epicenter of this principality — the seat through which Scottish princes held sway over the Cumbrian lands.

• 12th–13th centuries — Integration
  The principality was fully merged into the Kingdom of Scotland, while the southern Cumbrian lands fell under English administration. The memory of the “Bailiwick of Ennerdale” as a core jurisdiction survived in manorial and feudal traditions, linking back to the ancient principality.

Historical Names of Cumbria

• Regnum Cumbrorum — Kingdom of the Cumbrians (Latin).

• Alt Clut — “Rock of the Clyde” (Brittonic).

• Ystrad Clud / Ystrad Clwyd — “Valley of the Clyde” (Welsh).

• Strathclyde / Strath Cluaide — Later Gaelic/Scots name for the kingdom.

• Cumbria — Broad northern Brittonic land; modern county name (1974).

• Cumberland — “Land of the Cumbrians,” medieval English shire.

• Westmorland — Neighboring English shire often associated with Cumbria.

• Yr Hen Ogledd — “The Old North,” Welsh name for the Brittonic kingdoms.

• Rheged — Earlier Brittonic kingdom, often associated with western Cumbria.

• Cymry / Cumbri — Ethnonyms for the people, meaning “kinsfolk.”

• Princeps Cumbrorum — Title of David I: “Prince of the Cumbrians.”

The Bailiwick of Ennerdale as Epicenter

• Geographic Heart: Ennerdale lay at the crossroads of Cumbrian identity, midway between Strathclyde and Cumberland, facing both the sea and the mountain passes.

• Political Core: As a bailiwick and later a liberty, Ennerdale embodied the governance of the old principality, standing as a microcosm of Cumbrian independence.

• Continuity: Even when Cumbria was absorbed by the Scots and English, Ennerdale’s bailiwickal identity preserved the memory of the Cumbrian principality.

Legacy

The Regnum Cumbrorum was the last major Brittonic kingdom of the north. Its memory lived on in titles, in the diocesan structure of Glasgow, and in local liberties such as the Bailiwick of Ennerdale, which symbolized the epicenter of Cumbrian rule. The modern county name “Cumbria” (1974) echoes this deeper identity that once bridged Scotland and northern England.