Bulgarian archeologists stumbled upon the remains of an ancient Roman legion's headquarters (Principia) in the Danube city of Ruse, reports say.
The building dates back to IVth century AD and was located in the present-day center of the city, near where the Military Club now lies.
Digs started in 2005, because of a hotel construction, but were soon turned into an archaeological quest as builders stumbled upon the remains.
Coins found at the scene helped determine the age of the building, as they had been minted during the rule of Emperor Constantine and his sons. Among the discoveries that thrilled the archaeologists were a flag chamber and the foundations of the building's main entrance. The whole principia spread on about 400 square meters, digs showed.