Archduchess of Austria, queen of Hungary and Bohemia (1740–80). The daughter of the Emperor Charles VI, Maria Theresa married the future Emperor Francis I in 1736 and succeeded to the Habsburg dominions in 1740 by virtue of the Pragmatic Sanction (by which her father made provision for her to succeed him). Her accession triggered the War of the Austrian Succession (1740–48), during which Silesia was lost to Prussia. She attempted but failed to regain Silesia from the Prussians in the Seven Years War (1756–63). After the death of Francis I in 1765 she ruled in conjunction with her son, the Emperor Joseph II.