In the process of constructing a new church building, the city of Cologne has stumbled on something unexpected.
Last year, researchers found the walls of a 2,000-year-old building while working on construction for a new church community center in the middle of Cologne. They thought it could have been the ruins of a public meeting hall. But last month, researchers concluded it’s more likely to be a Roman public library dating back to between 150 and 200 A.D.
The niches in the walls are 80 centimeters deep, and according to Kölner Stadt-Anzeiger (link in German), were too small for statues. After archaeologists compared the structure to others in Ephesus, Pergamon, Alexandria, and Rome, they thought the spaces might be better suited for rolled up papyrus or parchment. Dirk Schmitz from the Roman-Germanic Museum of Cologne tells The Guardian that he estimates the building could have held 20,000 scrolls, a space he called “quite huge.”
Researchers believe the 20-by-9-meter structure is the oldest known public library in Germany.
The ancient library will be visible from the new underground parking lot for the community center.
Correction: An earlier version of this article stated the building’s niches were 80 centimeters wide, rather than 80 centimeters deep.