Charles VI, Holy Roman Emperor

Charles VI became Holy Roman Emperor in 1711 after his brother Joseph I's death, having already failed to claim the Spanish throne despite years of war over it. He married Elisabeth Christine of Brunswick-Wolfenbüttel in 1708, and when their only surviving son died in infancy, he faced a problem: no male heir. In 1713, four years before Maria Theresa's birth, he issued the Pragmatic Sanction to allow female succession, sidelining his elder brother's daughters and breaking an earlier pact. He spent the rest of his reign extracting recognition from every major power in Europe - Britain, France, Spain, Prussia, Russia, the papacy - often at severe cost, including shutting down Austria's Ostend Company. When he died in October 1740, France, Spain, Saxony-Poland, Bavaria, and Prussia immediately reneged, plunging Maria Theresa into the eight-year War of the Austrian Succession the moment she took the throne.