Habsburg-Lorraine in the context of John II, Duke of Lorraine

The Principality of Transylvania, from 1765 the Grand Principality of Transylvania, was a realm of the Hungarian Crown ruled by the Habsburg and Habsburg-Lorraine monarchs of the Habsburg monarchy (later Austrian Empire) and governed by mostly Hungarians. After the Ottomans were ousted from most of the territories of medieval Kingdom of Hungary, and after the failure of Rákóczi's War of Independence (1703–1711), the Habsburg dynasty claimed the former territories of the Principality of Transylvania under the capacity of their title of "King of Hungary". During the Hungarian Revolution of 1848, the Hungarian government proclaimed union with Transylvania in the April Laws of 1848 (after the Transylvanian Diet's confirmation on 30 May and the king's approval on 10 June for Transylvania to become once again an integral part of Hungary). After the failure of the revolution, the March Constitution of Austria decreed that the Principality of Transylvania be a separate crown land entirely independent of Hungary. In 1867, as a result of the Austro-Hungarian Compromise, the principality was reunited with Hungary proper.

Francis I (Francis Stephen; French: François Étienne; German: Franz Stefan; Italian: Francesco Stefano; 8 December 1708 – 18 August 1765) was Holy Roman Emperor from 1745 to 1765, Archduke of Austria from 1740 to 1765, Duke of Lorraine and Bar from 1729 to 1737, and Grand Duke of Tuscany from 1737 to 1765. He became the ruler of the Holy Roman Empire and Tuscany through his marriage to his second cousin Maria Theresa of Austria, daughter of Emperor Charles VI. Francis was the last non-Habsburg monarch of the Empire. The couple were the founders of the Habsburg-Lorraine dynasty, and their marriage produced sixteen children.

Francis was the oldest surviving son of Leopold, Duke of Lorraine, and the French princess Élisabeth Charlotte d'Orléans. Duke Leopold died in 1729 and was succeeded by his son. In 1736, Francis married Maria Theresa. In 1738, he left the Duchy of Lorraine and Bar for the deposed Polish king Stanisław Leszczyński in exchange for the Grand Duchy of Tuscany, as one of the terms ending the War of the Polish Succession. Following the death of his father-in-law, Charles VI, in 1740, Francis and Maria Theresa became the rulers of the Habsburg domains. Maria Theresa gave her husband responsibility for the empire's financial affairs, which he handled well. Francis died in 1765 and was succeeded by their son, Joseph II, who co-ruled Austria alongside Maria Theresa.

Joseph II (13 March 1741 – 20 February 1790) was Holy Roman Emperor from 18 August 1765 and sole ruler of the Habsburg monarchy from 29 November 1780 until his death. He was the eldest son of Empress Maria Theresa and her husband, Emperor Francis I, and the brother of Marie Antoinette, Leopold II, Maria Carolina of Austria, and Maria Amalia, Duchess of Parma. He was thus the first ruler in the Austrian dominions of the union of the Houses of Habsburg and Lorraine, styled Habsburg-Lorraine.

Joseph was a proponent of enlightened absolutism like his brother Leopold II; however, his commitment to secularizing, liberalizing and modernizing reforms resulted in significant opposition, which resulted in failure to fully implement his programs. Meanwhile, despite making some territorial gains, his reckless foreign policy badly isolated Austria. He has been ranked with Catherine the Great of Russia and Frederick the Great of Prussia as one of the three great Enlightenment monarchs. False but influential letters depict him as a somewhat more radical philosophe than he probably was. His policies are now known as Josephinism. He was a supporter of the arts, particularly of composers such as Wolfgang Amadeus Mozart and Antonio Salieri. He died with no known surviving legitimate offspring and was succeeded by his younger brother Leopold II.