Saxony joined Austria in the Second Silesian War, which erupted after Prussia proclaimed to keep Charles VII as Holy Roman Emperor and invaded Bohemia on 15 August 1744. The true cause behind the invasion was Frederick's personal expansionist ideas and goals. On 8 January 1745, the Treaty of Warsaw united Great Britain, the Habsburg Monarchy, the Dutch Republic and Saxony into what became known as the "Quadruple Alliance", which was aimed at securing the Austrian throne for Maria Theresa. Soon-after Charles VII died of gout in Munich, which weakened the Prussians. However, Prussia still maintained military superiority; the successful battles of Hennersdorf and Kesselsdorf opened the way to Dresden, which Frederick occupied on 18 December. The Treaty of Dresden was eventually completed on Christmas Day (25 December) and Saxony was obliged to pay one million rixdollars in reparations to the Prussian state. The treaty ended the Second Silesian War with a "status quo ante bellum".