Maria Theresa Walburga Amalia Christina (German: Maria Theresia Walburga Amalia Christina) (13 May 1717 – 29 November 1780) was the only female ruler of the Habsburg dominions and the last of the House of Habsburg. She was the sovereign of Austria, Hungary, Croatia, Bohemia, Mantua, Milan, Lodomeria and Galicia, the Austrian Netherlands and Parma. By marriage, she was Duchess of Lorraine, Grand Duchess of Tuscany and Holy Roman Empress.
She started her 40-year reign when her father, Emperor Charles VI, died in October 1740. Charles VI paved the way for her accession with the Pragmatic Sanction of 1713 and spent his entire reign securing it. Upon the death of her father, Saxony, Prussia, Bavaria and France repudiated the sanction they had recognised during his lifetime. Prussia proceeded to invade the affluent Habsburg province of Silesia, sparking a nine-year conflict known as the War of the Austrian Succession. Maria Theresa would later unsuccessfully try to reconquer Silesia during the Seven Years' War.