Union of Bulgaria and Romania.
Several attempts and proposals were made to unify Bulgaria and Romania in the 19th and early 20th centuries, under a federation, a personal union or a confederation. Earlier, Bulgarians and Romanians had lived together under the First Bulgarian, Second Bulgarian and Ottoman empires for centuries. After the establishment in 1878 of an autonomous Bulgarian principality, there were several unsuccessful Romanian nominees for its throne. In 1886, Bulgarian leader Stefan Stambolov tried again to establish a personal union with Romania, and negotiations were conducted. All such proposals ultimately failed because of cultural and political differences and opposition from Austria-Hungary and especially Russia, which even threatened to invade both countries. Approaches to effect a union were attempted again during the communist era, but the Soviet Union strongly rejected them. The accession of both countries into the European Union has led to speculation about a new future revitalization of the idea.
