It was not strange that the unexpected death of Charles VI in October 1740 led to a war. Though the Pragmatic Sanction had been guaranteed by most European Powers, respect for treaties seemed an inadequate safeguard of a State that was ill-prepared to resist aggression. Maria Theresa inherited an empty treasury and a weak and demoralised army. Her father's ministers, whom she continued in office, were old and incompetent. She herself had received no political training, and her husband Francis was an unpopular mediocrity. What made her position worse was that she could not count on the loyalty of her subjects. Many of the nobles in Austria and Bohemia were ready to submit to a rival claimant, Charles Albert, elector of Bavaria. The Magyar nobility appeared more likely to be eager to weaken Habsburg authority in Hungary than to defend Maria Theresa. Charles Albert, on his part, had made no secret of his intention to claim to be the heir of Charles VI; bad though that claim was, he genuinely believed in it. But by himself he could do nothing: he was in debt; his forces were weak; his generals and ministers incapable. His dependence was on French support, and of that he had good hope.

By a treaty made in 1727 France had pledged herself to support such just claims as the elector might have to any of the Habsburg dominions on the death of Charles VI without male heirs. In 1735, however, France had guaranteed the Pragmatic Sanction; but it could be contended that this guarantee was without prejudice to the right of a third party, and this should have been realised in Vienna, since during Charles's last years France had proffered, though without response, her good offices for a settlement of the Bavarian claim.