The Grand Principality of Transylvania was a Hungarian princedom that ruled over Transylvania from 1711 to 1867, with Hermannstadt (Sibiu) and Klausenburg (Cluj) serving as its capitals throughout its history. The Austrians conquered Transylvania during the Great Turkish War and added it to the Habsburg Monarchy's crownlands in 1699. In 1711, the Habsburgs replaced the princes of Transylvania with imperial governors, and Maria Theresa proclaimed the Grand Principality of Transylvania in 1765. Southern Transylvania was settled by expelled German Protestants and Austrian crypto-Protestants from the 1730s to the 1750s, adding to a long-existing population of Transylvanian Saxons. However, the majority of the population remained Romanian peasants. During the Hungarian Revolution of 1848, Hungarian rebels called for Transylvania's reunion with Hungary, opposed by both the Austrian government and Wallachian revolutionaries. In 1849, Austria defined the principality as a separate crownland from Hungary, and the Transylvanian Military Frontier was abolished in 1853. In 1863-1864, the Transylvanian Diet proclaimed the equality of rights of Romanians and other Transylvanians. In 1865, however, the Emperor dissolved the Hermannstadt Diet and assembled a new one in Klausenburg, resulting in the new diet's vote for affiliation with Hungary. On 6 December 1868, Transylvania's incorporation into Hungary was codified.