Baptistery (Domhof) – Layers of Roman and Medieval Life

The name Aquae Granni, the Roman precursor of modern-day Aachen, points to Roman Aachen’s greatest asset: its hot springs! The mineral waters were quickly believed to have healing powers. Granni refers to Grannus, a Gallic deity associated with health and recovery. The earliest thermal baths date to around the turn of the millennium. From the outset, the Romans envisioned Aachen on a grand scale: even at its founding, the town had the air of a true city – 30 hectares in size, with wooden houses, thermal baths, and even a stone bathhouse with tiled roofs.

A City Growing Around Its Baths

In the early second century, Aquae Granni underwent a complete urban renewal. Emperor Trajan may have intended to elevate the vicus to a regional capital – a theory supported by stamped bricks and an inscription bearing his name. The original baths made way for a monumental square of more than 6,000 square metres, likely containing a forum and temple. Across the city, monumental new bath complexes were built.

Aquae Granni became one of the Roman Empire’s leading wellness centres and the only major spa in Germania Inferior.

Continuity into the Baptistery

The city’s Roman foundations continued to shape its urban life for centuries, as can be seen at the Baptistery in the Domhof. Near the northern exterior wall of the Baptistery, a fragment of a 2nd-century funerary monument is embedded in the masonry. In the chapel’s basement, excavations have revealed Roman and medieval buildings and multiple settlement layers, preserved as an Archaeological Zone.

Although access is currently limited to guided tours, a digital presentation is planned to make the site more widely accessible. The Baptistery illustrates how Aachen’s Roman urban structures provided the framework for later medieval development, highlighting nearly two millennia of continuous settlement and lasting influence!

Discover Roman Aachen on the VIA VIA Route, 2027

The Baptistery is one of ten stops along the VIA VIA Roman City Walk route of Aachen, which links the museum exhibit in Centre Charlemagne with visible archaeological remains across the city. You encounter on this route traces of Roman walls, floors, bath complexes, forums, and late-Roman fortifications, with interpretive panels, videos, and Roman “characters” providing context. Sites like the Baptistery illustrate how Aachen’s fascinating Roman past persisted through medieval times.

Are you ready to take a walk?

“‘The city smells of rotten eggs,’ Julia grimaces. My daughter is right. The thermal baths of Aquae Granni may be healing, but their sulphurous stench is unbearable. It doesn’t seem to bother the bathers, though. Our cart moves forward at a crawl through a crowd of shuffling people and wagons piled high with wood. ‘Most of it is for the baths,’ says a dark-skinned man walking beside us. ‘Every day, the thermae and the underfloor heating of the rich devour another piece of the forest. The baths heal the body, but not nature,’ he sighs, before vanishing again into the throng. Quintus Iulius has come up with the idea of bottling the spring water and selling it at the markets of Germania Inferior. Personally, I’m just looking forward to sliding into the warm water for a few hours — and talking with people from all corners of the Empire. Perhaps I’ll overhear some news about the situation in Rome. They seem to change emperors every few months this year. Murder and decapitation — not even the most curative water can wash that away.” – Ammulva Iucunda