The Battle of Rheinfelden was a military event in the course of the Thirty Years' War, consisting in fact of two battles to the north and south of the present-day town of Rheinfelden. On one side was a French-allied mercenary army led by Bernhard of Saxe-Weimar while the other side consisted of a joint Bavarian and Holy Roman Empire army and led by Johann von Werth and Federico Savelli. Bernhard was beaten in the first battle but managed to defeat and capture Werth and Savelli in the second.