A Roman-era building in Cologne is believed to be Germany’s oldest library.

A structure that is most likely Germany’s oldest library—dating back to sometime between 150 and 200 A.D.was identified after researchers compared the remains of a building unearthed in central Cologne to those of another Roman library. The building’s foundation, which was excavated last year during the construction of a protestant church’s new parish building, was previously thought to have been an assembly room. Now, it is believed that the structure was in fact a two-story-tall library that contained several thousand scrolls, according to the DW.

The head of the the archaeological monument authority in Cologne, Dirk Schmitz, told the Art Newspaper that a series of cavities in the structure’s wall provided a major clue in identifying the structure as a library. “There are niches along the inside of the walls which have remained intact,” Schmitz said. “They were almost certainly used to store the scrolls.” In addition, Schmitz believes that a statue of Roman goddess Minerva was most likely included in the building, tucked into an annex near the library.

The church plans to continue construction on building an underground parking lot and new parish hall, but told TAN that it will make sure the public can still access the remains of the Roman structure.