Battle of Oldendorf The Battle of Oldendorf ( ) on 8 July 1633 was fought as part of the Thirty Years ' War between the Swedish Empire and the Holy Roman Empire near Hessisch - Oldendorf , Lower Saxony , Germany . The result was a decisive victory for the Swedish Army . Prelude . The Landgrave of Hesse - Kassel , William V , as a Protestant ally of Sweden had campaigned in Westphalia , Ruhr area and the Sauerland , successfully reducing the imperial presence there . The imperial defense of the Weser area in 1633 was led by Jobst Maximilian von Gronsfeld . The battle was preceded by a Swedish siege of the nearby imperial - held town of Hameln , laid in March 1633 with support of Hessian and Lüneburgian troops . Battle . On 8 July , the Swedish army commanded by George , Duke of Brunswick - Lüneburg and Marshal Dodo zu Innhausen und Knyphausen faced an Imperial relief army commanded by Field Marshal Jobst Maximilian von Gronsfeld , Count John ( Johann , Jean ) of Merode and Lothar Dietrich Freiherr von Bönninghausen . Merode commanded 4 , 450 infantrymen and 1 , 245 cavalry troops , Bonninghausen 4 , 475 infantry and 2 , 060 cavalry , Gronsfeld 2 , 000 infantry and 600 cavalry . The armies met near Hessisch - Oldendorf , northwest of Hameln . Both armies attacked , a rare event in the Thirty Years ' War , which besides Oldendorf only occurred in the Second Battle of Breitenfeld . The left wing of the Swedish forces was commanded by the general of Landgraviate of Hesse - Kassel and later imperial field marshal Count Peter Eppelmann Melander von Holzapfel . Subsequently , field marshal Torsten Stålhandske led a Swedish brigade . Field marshal Gottfried von Geelen participated later in the battle on the imperial side . Gronsfeld was captured after his wing was routed by Melander , leaving over 3 , 000 dead and wounded and 1 , 000 prisoner . The Swedes lost 700 soldiers . Aftermath . The Swedish victory in Oldendorf and the subsequent victory in the Battle of Pfaffenhofen on 11 August balanced their defeat in the Battle of Steinau on 10 October . Overall , Swedish and Imperial forces were " on even terms " in 1633 . This only changed in the following year . While the Swedish forces won the Battle of Liegnitz on 8 May and the Battle of Landshut on 22 July , their defeat in the Battle of Nördlingen on 6 September 1634 brought about a change in the balance of power . Melander , the Swedish commander at Oldendorf , intrigued with the Holy Roman Emperor in 1635 to merge Hesse - Kassel ' s forces into the Imperial army and have Hesse - Kassel sign the Peace of Prague . These plans failed , and personal quarrels led him to leave service and to re - enter it as the Imperial commander of Westphalia in 1645 . The Peace of Prague reconciled many Protestant states with the Holy Roman Emperor , most notably the Electorate of Saxony . As a consequence , Sweden ' s and Hesse - Kassel ' s forces stood alone against a growing anti - Swedish , pro - Habsburg coalition in 1635 - a disequilibrium eventually stirring France ' s intervention in the Thirty Years ' War . In 1647 , Hessisch - Oldendorf became the winter quarters of the Swedish army commanded by Carl Gustaf Wrangel retreating from Bohemia , followed by the then imperial commander Melander who took his quarters in Hesse .