The earliest military fortification in Timok area Timacum Minus (lat. Timacum - Timok, hydronym; lat. Minus - "Reduce") was constructed in the valley of the Beli Timok river, near the village of Ravna, close to the Knjaževca. Archaeological investigations of the site have indicated the continuity of settlement from prehistoric times to the Middle Ages. The settlement reached its peak in the period of antiquity as Timacum Minus representing an important mining and metallurgical center.