The Roman Empire was divided in 395. Later the Croats entered the Western Roman Empire. The historical border between the Eastern and Western Roman Empire was the river Drina. It flows between present Serbia and Bosnia, and in the past it divided in political and cultural sense, two very different civilizations, which had been separated until the penetration of the Turks in the 16th century. Later in 1054 this division also defined the border of the two Churches, one under Byzantium (Constantinople) and the other under Rome. Let us mention that Montenegro and Albania belonged to the Western Church. In 1184 the Serbian Orthodox Church penetrated by military expansion to Montenegro. Until that time the territory of Montenegro was a part of Red Croatia. Serbia, and later Montenegro, developed on the heritage of the Eastern Roman Empire (or Byzantine Empire).
Oh, I get it now... You are no Brit.. You are either an Albanian, or self-hating Croatian who is ashamed of his Slav heritage, or one of those Montenegrines who also thinks that without Serbs Montenegro will be quickly accepted in EU (ha,ha..). Your anti-Serb attitude is so obvious and revealing..
And, BTW, what was the point of this post anyway?
FYI, Serbs also fluctuated between West Roman Empire and Bysantine Empire, depending what their interests were. In the end they opted for Byzantine Empire, so what? What does it have to do with anything on this thread?