In early 1848, revolution erupted in Europe, and by March it had ignited both Austria and Hungary. Hungary's Diet seized the opportunity to enact a comprehensive legislative program that, in effect, extricated the country from the Middle Ages. The Diet abolished serfdom and feudal privileges and proclaimed freedom of the press and religion. The Diet's reform legislation also provided for the union of Transylvania and Hungary. In April Emperor Ferdinand V (1835-48) swore to uphold the reforms, and on May 29, with a crowd in the street shouting "Union or Death!" the Transylvanian Diet voted for unification. Romanians had no voice in the decision.

Unification galvanized Romanian opposition. Thousands of peasants and miners gathered in Blaj to denounce union with Hungary and call for proportionate representation of Romanians in Transylvania's Diet and an end to ethnic oppression. Warfare began in September between Hungarian troops and imperial forces, and a month later Romanian troops under Austrian command battled the Hungarians in Transylvania. The Romanians sided with the Austrians, believing that the emperor would grant them equal rights in reward for their loyalty. Both sides committed atrocities, and for several months the Hungarians were victorious. In June 1849, however, the tsar heeded an appeal from Emperor Franz Joseph (1848-1916) and sent in Russian troops, who extinguished the revolution.

After quashing the revolution, Austria imposed a repressive regime on Hungary and ruled Transylvania directly through a military governor. German again became the official language, but the Austrians reinstated neither serfdom nor the nobles' monopoly on land ownership or tax-exempt status. Austria also abolished the Union of Three Nations and granted the Romanians citizenship. Former feudal lords hesitated to give up their land, however, and most of the newly freed serfs became sharecroppers on inferior land that barely yielded subsistence. These dismal conditions uprooted many Romanian families, who crossed into Walachia and Moldavia searching for better lives.

Data as of July 1989