Four years before the birth of Maria Theresa, faced with his lack of male heirs, Charles provided for a male-line succession failure with the Pragmatic Sanction of 1713.

Archduke Charles (baptized Carolus Franciscus Josephus Wenceslaus Balthasar Johannes Antonius Ignatius), the second son of the Emperor Leopold I and of his third wife, Princess Eleonore Magdalene of Neuburg, was born on 1 October 1685.

Charles III, as he was known, disembarked in his kingdom in 1705, and stayed there for six years, only being able to exercise his rule in Catalonia, until the death of his brother, Joseph I, Holy Roman Emperor; he returned to Vienna to assume the imperial crown.

[7] Not wanting to see Austria and Spain in personal union again, the new Kingdom of Great Britain withdrew its support from the Austrian coalition, and the war culminated with the Treaties of Utrecht, Rastatt and Baden three years later.

Since Habsburg possessions were subject to Salic law, barring women from inheriting in their own right, his own lack of a male heir meant they would be divided on his death.

The Pragmatic Sanction of 19 April 1713 abolished male-only succession in all Habsburg realms and declared their lands indivisible, although the Diet of Hungary only approved it in 1723.

It was this act that undermined the chances of a smooth succession as set out in a Pact arranged by his father, and obliged Charles to spend the rest of his reign seeking to ensure enforcement of the sanction from other European powers.

[12] Other signatories included Britain, France, the Dutch Republic, Spain, Russia, Denmark-Norway and Savoy-Sardinia, but subsequent events underlined Prince Eugene of Savoy's comment that the best guarantee was a powerful army and full treasury.

[13] In the first part of his reign, the Habsburg monarchy continued to expand thanks to the success in the Austro-Turkish War (1716–1718), adding Banat to Hungary and establishing direct Austrian rule over Serbia and Oltenia (Lesser Wallachia).

[15] Peace in Europe was shattered by the War of the Polish Succession (1733–1738), a dispute over the throne of Poland between Augustus of Saxony, the previous king's elder son, and Stanisław Leszczyński.

[19] The love of his life was Michael Joseph, Count Althann, a groom of the bedchamber, whom he called "my only heart, my comfort...my soul mate",[20] and with whom he slept regularly.

[23] Popular discontent at the costly war reigned in Vienna; Francis of Lorraine, Maria Theresa's husband, was dubbed a French spy by the Viennese.

Maria Theresa was forced to resort to arms to defend her inheritance from the coalition of Prussia, Bavaria, France, Spain, Saxony and Poland—all party to the sanction—who assaulted the Austrian frontier weeks after her father's death.

[32] At the time of Charles's death, the Habsburg lands were saturated in debt; the exchequer contained a mere 100,000 florins; and desertion was rife in Austria's sporadic army, spread across the Empire in small, ineffective barracks.