The Massacre of Verden, or the Bloody Verdict of Verden, was a massacre of Saxons in 782 near the present town of Verden in Lower Saxony, Germany, ordered by Charlemagne during the Saxon Wars.
In 782 A.D. some 4,500 Saxon leaders are said to have been beheaded for practicing their indigenous Germanic paganism, having officially, albeit under duress, converted to Christianity and undergone baptism. The river Aller was said to have been flowing red with their blood. Charlemagne's motives were to demonstrate his overlordship and the severity of punishment for rebellion.
The effect was that the Saxons lost virtually their entire tribal leadership and were henceforth largely governed by Frankish counts installed by Charlemagne. The Saxon leader, Duke Widukind, had escaped to his in-laws in Denmark, but soon returned. In 785 he, along with his people, was forced to convert to Christianity by Charlemagne.
On the issue of beheading the historian Ramsay MacMullen notes that in 681 a council of bishops at Toledo called on civil authorities to seize and behead all those guilty of non-Christian practices of whatever sort. These massacres were common on both sides throughout the Christianization of Europe, with similar events involving pagan Saxons, Germans and Celts and Christians documented in Britain and Ireland.
The controversy over the massacre was linked to disputes among German nationalists about the image of Charlemagne. Some Germans saw the victims of the massacre as heroic defenders of Germany's traditional beliefs, resisting the "foreign" religion of Christianity. Wilhelm Teudt mentions the site of the massacre in his 1929 book Germanische Heiligtümer ('Germanic Shrines'). Some Christian nationalists linked Charlemagne with the humiliation of French domination after World War I, especially the occupation of the Rhineland.
Hermann Gauch, Heinrich Himmler's adjutant for culture, took the view that Charlemagne (known in German as Karl der Große 'Karl the Great') should be officially renamed "Karl the Slaughterer" because of the massacre. He advocated a memorial to the victims. Alfred Rosenberg also stated that the Saxon leader Widukind, not Karl, should be called "the Great". During the Third Reich the massacre became a major topic of debate. In 1934, two plays about Widukind were performed. The first, Der Sieger (The Victor) by Friedrich Forster, portrayed Charlemagne as brutal but his goal, Christianization of the pagan Saxons, as necessary. Reception was mixed. The second, Wittekind, by Edmund Kiß, was more controversial for its criticism of Christianization. The play saw various disturbances during its run.
In 1935, landscape architect Wilhelm Hübotter was commissioned to build the Sachsenhain (German 'Grove of the Saxons') in Verden, a monument to commemorate the massacre consisting of 4,500 large stones. The monument was used as both a memorial to the event and as a meeting place for the Schutzstaffel. The memorial was inscribed to "Baptism-Resistant Germans Massacred by Karl, the Slaughterer of the Saxons". In the same year the annual celebration of Charlemagne in Aachen, where he is buried, was cancelled and replaced by a lecture on "Karl the Great, Saxon Butcher."
Sources wikipedia.com and http://www.fordham.edu/halsall/basis/einhard.asp