Archaeologists have unearthed the remains of two Roman temples and a sacrificial pit in Germany.

The building remnants, located at the site of a former Roman camp known as Haltern in northwestern Germany, are the first known instances of temples found at a Roman military site, according to a translated statement.

During excavations, archaeologists unearthed the clay frameworks of the rectangular buildings. The last time researchers explored the site was in 1928, but the findings were since reburied to help preserve the existing structures.

The twin temples were once part of a larger building complex that measured roughly 21,500 square feet (2,000 square meters). Archaeologists initially thought one of the buildings was used as a meeting house, or “schola,” for military officials and later as a workshop, based on some of the tools found strewn about the site. They’re currently not sure of the second building’s purpose.