St. Gereon
Romanesque church in Cologne with a ten-sided domed rotunda from the Hohenstaufen era — the largest surviving free-vaulted central-plan building of the Middle Ages north of the Alps.
since 1201
St. Gereon is one of Cologne's twelve great Romanesque churches, located in the Altstadt-Nord district. At its core lies a Late Antique central-plan structure from the 4th century, above which rises a ten-sided domed rotunda built during the Hohenstaufen period.
At a Glance
- Type
- Catholic basilica, one of Cologne's twelve Romanesque churches
- Location
- Altstadt-Nord, city district Innenstadt
- Core
- Oval central-plan building with nine conches, second half of the 4th century
- Reconstruction
- Expanded into a decagon around 1220 and vaulted with a dome
- Architectural style
- Romanesque and Gothic
- Named after
- Gereon of Cologne
- Protection
- Listed monument in North Rhine-Westphalia
The medieval decagon of St. Gereon, completed around 1220, is the largest surviving freely vaulted central-plan building of the Middle Ages north of the Alps – and its core dates back to a Roman oval structure from the 4th century whose dome was lightened by embedding empty clay amphorae into the concrete mass to reduce its weight.
Age comparison
Age compared with other places in Cologne.
Ancient Origins
Just outside the walls of the Roman Colonia to the northwest, a large Late Antique central-plan building was erected in the 4th century on the city's oldest burial ground. Its original purpose has never been conclusively established — it may have served as a mausoleum, memorial building, temple, or church. The earliest written record appears in a poem by Venantius Fortunatus dating from between 565 and 573. The surviving lower section is one of the oldest standing sacred buildings in Germany, alongside Trier Cathedral and the Basilica of Constantine in Trier.
Form and Construction
The oval of the original building was composed of circular arc segments radiating from four central points arranged in a cross around the room's centre — a form between a longitudinal and a central-plan layout. The vaulted oval space was surrounded by four windowed conches on each side and had an apse to the east; the dome measured 23.70 by 19.80 metres. To reduce its weight, hollow clay amphorae were built into the structure — a technique common in Roman domed buildings of the 4th century. The walls were clad in marble panels and gold-ground mosaics, and the floor was laid with mosaics as well.
The Hohenstaufen Rebuilding
Around 1220, the early Christian oval building was transformed into a decagon, raised in height, and crowned with a dome. This structure is considered the largest surviving free-vaulted central-plan building of the Middle Ages north of the Alps. The striking ten-sided dome remains the defining feature of the church to this day.
Scholarship
The Late Antique origins of the building were first established by Gertie Gretz and Otto Koch in 1939. After the wartime damage, further research by Armin von Gerkan, Otmar Schwab, Johannes G. Deckers, and Ute Verstegen deepened these findings. In terms of ground plan, the building is comparable to the so-called Temple of Minerva Medica in Rome, a domed central-plan structure built around 320 AD.
Timeline
- 2. Hälfte 4. Jh.Construction of the late antique oval central building with nine conches
- 565–573First written mention in a poem by Venantius Fortunatus
- um 590Second mention by Gregory of Tours (Librum miraculorum)
- 1201Completion / opening (according to Wikidata)
- um 1220Conversion of the oval building into a decagon, raised and vaulted with a dome
Gallery
Map
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Address
Gereonskloster 2
50670 Köln
Hours
Mo: 10:00–18:00
Di: 10:00–18:00
Mi: 10:00–18:00
Do: 10:00–18:00
Fr: 10:00–18:00
Sa: 10:00–18:00
So: 10:00–18:00
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Sources & links
- Official website
- Wikidata (retrieved 2026-06-24)
- Wikipedia (retrieved 2026-06-24, rev 267028610)
- Official website (retrieved 2026-06-24)
Auto-generated, last verified: 2026-06-27
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