Bosnia (region)
Bosnia (/Босна; ) is the northern region of Bosnia and Herzegovina, encompassing roughly 81% of the country; the other eponymous region, the southern part, is Herzegovina. "Bosnia" is an informal term for the whole country.
Bosanska Krajina
In the 6th century, today's northwestern Bosnia was part of the Roman province of Dalmatia. It fell under the jurisdiction of the Eastern Roman Empire. Shortly thereafter, Eurasian Avars and their Slavic subjects from central-eastern Europe invaded Dalmatia and settled in what is now Bosnia and Herzegovina. In the 7th century the Serbs and Croats formed principalities initially under the Eastern Roman Empire. It is unclear whether the region was under the Principality of Serbia or Duchy of Croatia in the Early Middle Ages. Fine, Jr. believes that what is today western Bosnia and Herzegovina was part of Croatia, while the rest was divided between Croatia and Serbia. Bosnia proper, called "Bosona" in the "De Administrando Imperio" ( 960), was a "small country" part of the Serbian principality.