After the Prussian Mainarmee (German for: army of the river
Main) had beaten the Bavarians at
Kissingen, the Bavarian army retreated to
Würzburg. The Prussians now turned west against the
VIIIth Federal Corps (troops of Württemberg, Baden, Hesse and Nassau) which protected
Frankfurt. After the VIIIth Corps had lost combats at Frohnhofen and
Aschaffenburg it gave up the defense of Frankfurt and went south-eastward to unite with the Bavarians at the river Tauber. The Prussian army followed.