Ys (Ker-Is) – Drowned Breton City
Ker Is · Ker-Ys · City of Ys · Ville d'Ys
Legendary 5th c. (Gradlon of Cornouaille) – folklore recorded 19th c.·Breton / Cornish Celtic Christian syncretism (Dahut as pagan vs Christian)·🇫🇷 Brittany, Finistère, Douarnenez Bay, France
About
About Ys (Ker-Is) – Drowned Breton City
Breton legend's opulent sea-walled city of King Gradlon in Douarnenez Bay, protected by sluice gates opened only at low tide, flooded when daughter Dahut (or Ahes) in demon-possessed trance stole keys and opened gates for lover at high tide – drowning Ys while Gradlon escapes on horse Morvac'h. Norman–Breton parallels to Ys flood myths track post-glacial submergence memory. No archaeology; 2021 Geoarchaeology (Nunn et al.) classes as northwest Europe postglacial sea-level rise folk memory. Composed in Barzaz Breiz (La Villemarqué 1846) from Theuriet oral tradition; church windows at Quimper show Gradlon.
Why it mattersTypical European 'lost land' folklore studied alongside Cantre'r Gwaelod and Lyonesse as cultural memory of Holocene transgression, not historical city.
Open questions
Mysteries & theories
Mysteries
- 01Why Douarnenez Bay selected vs other Brittany embayments?
- 02Gradlon horse escape motif parallels Welsh Cantre'r Gwaelod
Theories
- 01Gradual loss of coastal plain farmland over centuries compressed into single-night flood narrative (Guyot)
Theories are interpretations, not findings. The seal above tells you how much scholarly weight the place carries.
History
How it came to be
- Built
- Legendary – '5th c.' as capital of Cornouaille kingdom, 25 km NW Quimper
- Period
- Legendary 5th c. (Gradlon of Cornouaille) – folklore recorded 19th c.
- Culture
- Breton / Cornish Celtic Christian syncretism (Dahut as pagan vs Christian)
- Purpose
- Mythic wealthy sea-defended capital; cautionary flood tale
- Abandoned
- Mythic flood – single night submergence
- Rediscovered
- 19th c. antiquarians locate imagined at Pouldavid estuary; fishermen's nets snagging reported
- Excavation
- Not applicable
5th c. (legend)
Gradlon rules Cornouaille from Ys
1846
Barzaz Breiz publication codifies Ys narrative (La Villemarqué)
1926
Guyot systematizes Breton submerged land traditions
2021
Nunn et al. Geoarchaeology classifies as sea-level rise memory
On the ground
Structures & features
48.0928° N · 4.3292° W · -10 m · 3 mapped features
Pouldavid Estuary (mythic gate locus)
estuaryMouth of Pouldavid River where Ys walls imagined, Douarnenez
48.0850° N · 4.3200° WDouarnenez Bay (mythic city area)
bayBay waters where Ys supposed submerged 25 km NW Quimper
48.0928° N · 4.3292° WQuimper Cathedral Gradlon statue
statueEquestrian Gradlon commemorating legend
47.9970° N · 4.1020° W