During the Second Silesian War, Prussian troops crossed the Saxon border, and Saxony and Austria agreed to proceed together against Prussia. Saxon troops planned to cut off the Prussians in northern Silesia, while Austrian troops would advance from the south. But in June 1745, they were defeated at the Battle of Hohenfriedberg. Johann Adolf planned a new offensive campaign in September 1745, but he changed his mind two weeks later. Because of this, he was replaced as commander-in-chief by Count Frederick August Rutowski, an illegitimate half-brother of the King-Elector.