At the time, Austria still claimed the mantle of the Empire and was the chief force of the disunited German states. Until 1745, Maria Theresa was able to regain the Imperial crown from her Wittelsbach rival Charles VII by occupying his Bavarian lands, but, despite her Quadruple Alliance with Great Britain, the Dutch Republic and Saxony, she failed to recapture Silesia: The Second Silesian War started with Frederick's invasion into Bohemia in 1744 and after the Prussian victory at the 1745 Battle of Kesselsdorf, by the Treaty of Dresden the "status quo ante bellum" was confirmed: Frederick kept Silesia but finally acknowledged the accession of Maria Theresa's husband, Emperor Francis I. The terms were again confirmed by the final Peace of Aix-la-Chapelle in 1748.