When Maria Theresa’s father, Emperor Charles VI died in 1740; Maria Theresa’s sex meant that she was barred from becoming Holy Roman Empress in her own right. However, she did inherit many of her father’s family dominions which he had secured for her during his lifetime by pushing through an act called the Pragmatic sanction in 1713.
Despite agreeing to the Pragmatic sanction during Charles’s lifetime, some of the European powers retracted their support of Maria Theresa’s reign as soon as her father had died. Prussia and France claimed that as a woman, Maria Theresa should not be allowed to rule over the Habsburg thrones. This led to the War of the Austrian Succession which dragged all of Europe’s great powers into a drawn-out nine-year war.
In order to prevent further disputes over her reign and secure the safety of her own family lands which included Austria, Hungary and Bohemia, Maria Theresa and her husband worked hard to make sure that he was elected as the next Holy Roman Emperor. By securing the Imperial crown for Francis Stephen, Maria Theresa could once again bring most of Europe under her control and regain the areas once ruled over by her father.
In 1745 a peace treaty was signed between Austria and the Electorate of Bavaria, in which Maximilian III of Bavaria; whose father Emperor Charles VII had recently died, vowed to back Francis Stephen’s claim to the Imperial throne. On top of this, Maximilian agreed to secure the votes of the Electors of the Palatinate and Cologne. The Treaty of Füssen and the consequences of it were, therefore, important factors in Francis becoming Emperor. Maria Theresa had also made Francis co-regent of her lands because he did not previously hold enough land or high enough rank to be chosen as Emperor.
On 13 September 1745, Francis Stephen was elected as Holy Roman Emperor, the first of the new Habsburg-Lorraine line. Maria Theresa ruled alongside her husband as Empress consort and was heavily involved in Imperial politics. Francis Stephen was also recognised as Maria Theresa’s co-regent in her own dominions which led to the couple ruling over much of Europe together, as The Holy Roman Empire included vast territories such as Bavaria, Saxony and Brunswick.
After the death of her husband, Maria Theresa continued to hold the Habsburg lands and the Holy Roman Empire under her influence as she ruled alongside her son Joseph II.