Bulverket Lake Fortress (Tingstäde Träsk, Gotland)
Bulverket · Bulverket Tingstäde · Tingstäde Bulwark
Early Middle Ages (c.1120–1150 CE)·Medieval Gotlandic·🇸🇪 Gotland County, Tingstäde parish, Tingstäde Träsk lake, Sweden
About
About Bulverket Lake Fortress (Tingstäde Träsk, Gotland)
Massive 1130s timber platform fortress in Tingstäde Träsk lake, Gotland: 170 × 170 m square bulwark of ca. 25,000 pine logs forming a square grid with causeway to shore. Built c.1120s and burnt or dismantled within decades. Excavated by Lennart von Post 1927–38 and Johan Rönnby 1990s dendro-dated to c.1125. Purpose enigmatic – possibly war refuge, toll station or meeting bulwark during Gotland civil strife, giving the lake its name (Ting = assembly).
Why it mattersMassive 1130s timber platform fortress in Tingstäde Träsk lake, Gotland: 170 × 170 m square bulwark of ca. 25,000 pine logs forming a square grid with causeway to shore. Built c.1120s and burnt or dis
Open questions
Mysteries & theories
Mysteries
- 01Why such massive lake investment for short-lived use
- 02Was Bulverket a Gotlandic Ting bulwark or war refuge from mainland kings?
Theories
- 01Bulverket as elite refuge during Danish–Gotlandic conflict 1120s
- 02Assembly platform for Ting law council on neutral lake ground
Theories are interpretations, not findings. The seal above tells you how much scholarly weight the place carries.
History
How it came to be
- Built
- c. 1125 CE (dendrochronology)
- Period
- Early Middle Ages (c.1120–1150 CE)
- Culture
- Medieval Gotlandic
- Purpose
- Lake fortress / assembly bulwark – refuge or contested power base
- Abandoned
- c. 1150 CE (burnt/collapsed)
- Rediscovered
- 1927 von Post; 1989–96 Rönnby
- Excavation
- Partially excavated
c. 1125 CE (dendrochronology)
Initial construction
c. 1524 CE
Major expansion
On the ground
Structures & features
57.7360° N · 18.6420° E · 45 m · 2 mapped features
Bulverket Square Platform
platform170 m square timber grid of pine logs 2.5 ha in lake centre
57.7365° N · 18.6425° EBulverket Shore Causeway
causewaySubmerged timber causeway linking platform to northern shore
57.7375° N · 18.6435° E