Battle of Drakenburg The Battle of Drakenburg ( ) took place on 23 May 1547 to the north of Nienburg , between the Protestant army of the Schmalkaldic League and the imperial troops of Eric II , Duke of Calenberg . It resulted in an imperial defeat . Eric was forced to swim over the Weser River to save his own life . As a consequence , the imperial troops left northern Germany , contributing to freedom of religion for Lutherans and Catholics in northern Germany . Context . The Schmalkaldic League had already been defeated in the Schmalkaldic War by losing the Battle of Mühlberg on 24 April 1547 . The signing of the Wittenberg Capitulation on 19 May virtually dissolved the league . Nonetheless , the northern German members of the Schmalkaldic League still resisted the Catholic Holy Roman Emperor Charles V . Siege of Bremen . In January 1547 , the imperial colonel and mercenary leader Christoph von Wrisberg recruited men in Münsterland . Via the Prince - Bishopric of Osnabrück and Minden , which were still loyal to the emperor , Wrisberg ' s army marched to Bremen to begin besieging the city . In April the 19 - year old Duke Eric II joined the besieging army , which numbered 12 , 000 men with Eric ' s reinforcements . In May , Eric was informed that a Protestant army was pillaging and plundering his Principality of Calenberg and that this army was on its way to Bremen to liberate the city . Because the unsuccessful siege had taken months , using up the supplies , killing a quarter of his " Landsknechte " , and creating the danger of a mutiny , Eric decided to abandon the siege . Deployment . Imperial troops . The imperial troops left Bremen on 22 May , marching rapidly to attack the Protestant army . The units of the two military leaders Eric and Christoph von Wrisberg travelled along the Weser separately , one on each bank ; they wanted to reunite at a river crossing . Wrisberg ' s troops lagged behind , however , because the sand paths caused problems . The young and ambitious duke did not wait for the latecomers and had his mercenaries march more quickly . After Eric was informed of the approach of the enemy near Drakenburg , he ordered his soldiers to get into battle formation . He had about 6 , 000 " Landsknechte " , an unknown number of horsemen , and seventeen cannons at his disposal . He positioned them east of Drakenburg towards Heemsen on an open field . He chose a corrugated terrain with sand dune s of up to fifteen meters in height . He regarded this as an ideal secure position to meet the enemy from . His cannons would have an open field of fire as a result of their more elevated position . Additionally , his troops had the advantage of having both the sun and the wind behind them . His troops did not , however , have any avenue for evasion or retreat , since the battlefield was bordered by swamps , wetlands , and the Weser River . Protestants . Elector John Frederick I of Saxony had led the Protestant army shortly before his capture in the Battle of Mühlberg . Originally , the army had only consisted of several " Fähnlein " of " Landsknechte " led by Albrecht VII , Count of Mansfeld . It had marched from Saxony via Nordhausen , Northeim , and Braunschweig to aid the besieged city of Bremen . Troops from Braunschweig , Hildesheim , Hamburg , and Magdeburg had joined the army . Thus , the army consisted of a total of 26 " Fähnlein " , or approximately 6 , 500 men , giving them a slight numeric advantage . Battle . The Protestant troops came from the east and reached Eric ' s troops , who were entrenched on the dunes . The Schmalkaldic attackers availed themselves of a tactic attributed to Brun von Bothmer , a captain from Brunswick . He knew the area well as he lived there as a child and proposed a pincer movement with a second offensive at the Catholics ' rear . Bothmer led about one thousand mounted arquebus iers to attack from the north covertly . Both parties began the battle with simultaneous shelling and assaults . In doing so , Eric ' s battle formation faltered . Additionally , the Protestant cavalry divided the imperial forces by riding in between the hills . In the chaos , Eric ' s cavalry fled , inflicting losses upon their own infantry . The Catholic forces ' escape route had been cut off by the Schmalkaldic forces as well as the nearby swampland . The only escape was the Weser River , which was flooded with spring runoff . Approximately 1 , 000 imperial mercenaries drowned while looking for a ford . Duke Eric II swam across the river with great difficulty , but survived . Rearguard action . The units under the command of Wrisberg reached the battlefield on 23 May , but the battle was already over . Because of their numeric inferiority they retreated towards Verden . About ten kilometers north of the battlefield , the soldiers encountered the Tross of the Protestants near Hassel . It was only protected by a few soldiers , equivalent to about one " Fähnlein " . The imperial forces overpowered the weak Schmalkaldic forces , seizing their war chest of about 100 , 000 gold guilder , which eventually they gave to Emperor Charles V . Consequences . As a result of the Battle of Drakenberg , the Imperial army of Eric II virtually ceased to exist ; Wrisberg ' s troops escaped to the Netherlands and disbanded . The Protestant victory contributed to the stability and freedom of religion for Lutherans and Catholics in northern Germany . The two surviving leaders , Christoph von Wrisberg and Eric II , despised each other for the rest of their lives , accusing each other of being responsible for the defeat .