Upon the death of the Holy Roman Emperor Charles VI in 1740, his daughter Maria Theresa succeeded to the throne. Rule of the Empire had previously been restricted to male heirs. Three months later, Frederick II of Prussia capitalised on her weak position by allying with France and invading Silesia. Britain, Hanover and the Dutch Republic formed an alliance to support Maria Theresa and counter Prussian expansionism. The War of the Austrian Succession was to be the proving ground of the Duke of Cumberland. Britain’s participation in the conflict was ended by the Peace of Aix-la-Chapelle, agreed with France in October 1748.