The so-called "Romanians" are the Vlachs who inhabited the territory just north of the Danube in Roman times, and today. Wallachia (home of the Vlachs), represented the outer limit or Roman expansion. The name of their country, Romania, is a take-off on Roman, and their language is recognizably derived from Latin. In these regards, Romania is the most "Latin" country in the Balkans, and in fact outside of Italy, France, Spain and Portugal.
During the Middle Ages, Romanian territory was crossed by the Magyars from modern Russia, on their way to Hungary, and Bulgars on their way to modern Bulgaria. Afterward, the Romanians were subjects of Turkey. The Vlachs were unable to repel any of these people, yet they were not crushed or absorbed by them.
How did the Vlachs manage to retain a semblance of "Romaness" when surrounding areas such as Bulgaria, Greece and Yugoslavia did not? And maybe the related question is what caused them to be more "Roman" in the first place than their neighbors?