During the mid 18th century, the king of Prussia, Frederick William II, took advantage of an opportunity to grab lands in Austria. The Holy Roman Emperor, Charles IV, was without male children, so he brought about the Pragmatic Sanction which ensured that his domains could be inherited by his daughter, Maria Theresa. Frederick William I, the father of Frederick William II, had agreed to this. However, Frederick William II had a claim to Silesia, which belonged to Austria. The acquisition of Silesia would make the Prussian territories more continuous. In addition, Frederick William was maintaining an extremely costly 100,000 strong standing army that was doing nothing, so why not put it to use? He had to overcome the problem that his father had approved the Pragmatic Sanction, so he got someone to write an argument against it that he even said was totally absurd. Frederick William invaded Austria in 1740, and began the War of the Austrian Succession. Austria found itself with no friends, so it turned to the Hungarians for assistance but they provided only a little over 20,000 men when they promised 100,000. Eventually the Austrians seemed to be gaining the upper hand and Prussia slacked off a little, so France stepped in and encouraged them to continue in their efforts. The war was concluded with the Treaty of Aix-la-Chapelle in 1748 in which Austria gave up Silesia to Prussia. The Austrians never got over the loss of Silesia, and this animosity lead to the Seven Years’ War which in turn led to the Diplomatic Revolution.