Vladimir Georgiev studied the distribution of place names to determine the extent of Thracian and Dacian populations. Toponyms formed from -dava are thought to derive from the Dacian for city or fort. Vladimir found marked about 40 of 50 on his map and these cover the areas of modern Romania, northern Bulgaria and north-eastern Serbia. The later area may have been taken by Dacia in the 2nd century BC.
The Thracian toponyms of -para for village, -bria for town and -diza for fortress all lie south of the Danubian plain suggesting that Thracians only extended north to the Balkan mountains.