In medieval times, the Romanian Principality of Moldova was an Ottoman vassal state. However, in 1812 the eastern part was handed over to Russia. In 1918, following the Russian Revolution, Moldova declared independence and united with neighboring Romania.
This led to the establishment of an alternative Soviet Moldovan administration on the east bank of the Dniester River. When Moldova was conquered by Russian forces during the Second World War, these two parts were united to form the Moldavian Soviet Socialist Republic – one of the 15 constituent republics of the USSR.
As the Soviet Union weakened, the eastern part of the republic, Transnistria, sought to become a separate republic within the USSR. When this option became obsolete with the collapse of the Soviet Union, it instead proclaimed independence.
In March 1992, the government of the newly independent Republic of Moldova attempted to take back Transnistria. However, this was thwarted by Russian forces in the territory.
Today, Transnistria exists as a de facto state. But, unlike other cases where Russia has intervened, it remains wholly unrecognized on the world stage. Indeed, even Moscow hasn’t recognized it.
Looking ahead, given that peace talks are focused clearly on reunification, most observers believe that it will eventually be reunited with Moldova. Indeed, in many ways, it’s perhaps the most likely of all the de facto states to be eventually resolved by the territory’s reintegration into the parent state.