Francis I, Holy Roman Emperor in the context of "Duke of Parma and Piacenza"

The House of Habsburg-Lorraine (German: Haus Habsburg-Lothringen) originated from the marriage in 1736 of Francis III, Duke of Lorraine and Bar, and Maria Theresa of Austria, later successively Queen of Bohemia, Queen of Hungary, Queen of Germany, Queen of Croatia and Archduchess of Austria, etc. etc. Its members form the legitimate surviving line of both the House of Habsburg and the House of Lorraine, and they inherited their patrimonial possessions from the female line of the House of Habsburg and from the male line of the House of Lorraine.

The House of Lorraine's branch of Vaudémont and Guise became the main branch after a brief interlude in 1453–1473, when the duchy passed in right of Charles de Bourbon's daughter to her husband, John of Calabria, a Capetian. Lorraine reverted to the House of Vaudémont, a junior branch of the House of Lorraine, in the person of René II, who later added to his titles that of Duke of Bar.

Marie Antoinette (/ˌæntwəˈnɛt, ˌɒ̃t-/; French: [maʁi ɑ̃twanɛt] ; Maria Antonia Josefa Johanna; 2 November 1755 – 16 October 1793) was the last queen of France before the fall of the monarchy during the French Revolution. She was the wife of King Louis XVI.

Born an archduchess of Austria, she was the penultimate child and youngest daughter of Empress Maria Theresa and Emperor Francis I of the Holy Roman Empire. She married Louis Auguste, Dauphin of France, in May 1770 at age 14, becoming the Dauphine of France. On 10 May 1774, her husband ascended the throne as king, and she became queen.

Queen of the Romans (Latin: Regina Romanorum, German: Königin der Römer) or Queen of the Germans were the official titles of the queens consort of the medieval and early modern Kingdom of Germany. They were the wives of the King of the Romans (chosen by imperial election), and are informally also known as German queen (German: Deutsche Königin). A Queen of the Romans also became Holy Roman Empress if her husband was crowned Holy Roman Emperor, in the Middle Ages usually by the Pope in Rome during an Italienzug. Most elected Kings of the Romans did, but some never made it that far, and thus their wives only ever achieved the status of Queen of the Romans.

Empress Maria Theresa (1745–1780) is often considered to be a ruler in her own right, as she was Queen regnant of Bohemia and Hungary, and although her husband Francis I was crowned Holy Roman Emperor in 1745, it was she who ruled the Empire and continued to do so even after Francis' death in 1765 before ruling jointly with her son Emperor Joseph II.

The House of Lorraine (German: Haus Lothringen) originated as a cadet branch of the House of Metz. It inherited the Duchy of Lorraine in 1473 after the death without a male heir of Nicholas I, Duke of Lorraine. By the marriage of Francis of Lorraine to Maria Theresa of Austria in 1736, and with the success in the ensuing War of the Austrian Succession (1740–1748), the House of Lorraine was joined to the House of Habsburg and became known as the House of Habsburg-Lorraine (German: Haus Habsburg-Lothringen). Francis, his sons Joseph II and Leopold II, and his grandson Francis II were the last four Holy Roman emperors from 1745 until the dissolution of the empire in 1806. The House of Habsburg-Lorraine inherited the Habsburg Empire, ruling the Austrian Empire and then Austria-Hungary until the dissolution of the monarchy in 1918.

Although its senior agnates are the dukes of Hohenberg, the house is currently headed by Karl von Habsburg (born 1961), grandson of the last emperor Charles I.

Archduke Leopold Johann of Austria (13 April 1716 – 4 November 1716), was the last-born male descendant from the House of Habsburg. The only son and long-hoped heir of Charles VI, Holy Roman Emperor, with his and his father's death in 1740, the Habsburg male line died out completely, being succeeded by the House of Habsburg-Lorraine (originated by the marriage of Leopold Johann's younger sister Maria Theresa and Francis III Stephen, Duke of Lorraine) who ruled the Habsburg domains until their dethronement following World War I in 1918.

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.