Many Romans stayed and intermarried with the Dacians, helping to shape the customs and language of the region.
From the 200s through the 1100s, there was a series of invasions by various tribes from the north, including the Magyars and the Saxons.
The northern region developed into a principality called Transylvania, the south into a principality called Walachia, and the east into Moldavia.
Throughout the fourteenth and fifteenth centuries, Walachia and Moldavia battled repeated invasions by the Ottoman Empire.
Serious environmental problems include soil erosion and water and air pollution from unregulated industrial development.