could have survived in ancient Dacia as an language island surrounded by Slavs. An alternative theory is therefore that the Romanians came from south of the Danube. It is proposed that after the fall of the Roman Empire, the various Romanised peoples of the Balkans migrated northward into modern Romania.
This theory, too, has been criticised by writers for evidence:

The fact that a migration of such proportions left not even the smallest trace in the places where it supposedly had started, or in the ones where it ended, remains inexplicable. On the other hand, the eleventh-century Byzantine author Kekaumenos knew of clashes between Vlachs in Serbia and the Byzantine authorities. According to him, following those clashes, the Vlachs withdrew southwards, to Epirus, Macedonia, and Hellas.
 - Spinei, Victor. TheRomanians and the Turkic Nomads North of the Danube Delta from the Tenth to the Mid-Yhirteenth century. Vol. 6. Brill, 2009.

Regardless, there is general consensus that the ancestors of the modern Romanians were Romanised during the Roman Empire, and for whatever reason, retained that Latin heritage. In this respects it is no different from France or Spain, which also remain Romance countries.

A:

In addition to the excellent answer by Semaphore, there are some details about why Romania kept a much stronger character of the Latin culture and language, compared with surrounding countries.
The influence of the French Revolution ( 1789 - 1799) was felt all across Europe. At the time, the territory of the modern Romania, while populated by people of same descent and similar language, was divided between the