Er zijn nog geen Nederlandstalige annotaties. Hier volgen annotaties in het Engels.
The medieval fortress Vratica ("little gate"), which shares or gave its name with nearby Vraca (Vratsa), was named so in reference to the narrow pass through the Balkan Mountains. Remains date from Antiquity and the Middle Ages. On the basis of general geogrpaphical correspondence and the suggestive name, it is thought that the Roman name of the fortress was Valvae ("double doors"), recorded by Prokopios in Greek as Balbai.