Saxon Rebellion

The Saxon Rebellion or Rebellion of the Saxons (Sachsenkrieg) refers to the struggle between the Salian dynasty ruling the Holy Roman Empire and the rebel Saxons during the reign of King Henry IV of Germany. The conflict reached its climax in the period from summer 1073 until the end of 1075, in a rebellion that involved several clashes of arms.

Origins
Undercurrents of discord between the Salian royal family and the Saxons already existed under Henry's father, Emperor Henry III. This may have been primarily due to his Rhenish Franconian origin as well as his numerous stays in the Imperial Palace of Goslar, which were associated with a disproportionately high economic burden on the surrounding population. With the accession of Henry IV in 1065 this conflict intensified, as Henry made demands on numerous Imperial domains (Reichsgüter) in the centre of the Saxon heartland around the Harz mountains—especially the silver mines of Rammelsberg. To secure these estates he initiated a castle building programme, erecting numerous fortresses along the range, the most prominent being the Harzburg. This was perceived as a threat by the Saxons. In addition, these castles were staffed with ministeriales of Swabian origin, who frequently plundered the Saxon population to make up for their lack of income.

In 1070 the Saxon count Otto of Nordheim, Duke of Bavaria since 1061, had been accused by the ministerialis Egeno I of Konradsburg of planning an assault on the king's life. Otto was deposed and banned, nevertheless he gained support by the son of the Billung duke Ordulf of Saxony, the young Magnus. King Henry IV had both captured and arrested. While Otto was pardoned, Magnus remained in custody at the Harzburg and was not released even after his father's death in 1072, as he showed no intention to renounce the Saxon ducal dignity.

Beginning of the rebellion
According to the chronicler Lambert of Hersfeld, the Saxon princes came to the Imperial Palace of Goslar on 29 June 1073 in order to point to these abuses and demand improvements. Henry IV refused to enter discussions and then fled from the large, advancing Saxon army to the nearby castle of Harzburg, where he was besieged by the Saxon rebels, again led by Count Otto of Nordheim together with Bishop Burchard II of Halberstadt. The king, however, was able to escape on the night of 10 August 1073, allegedly through the castle's well shaft. Henry fled across the Harz mountains reaching the Landgraviate of Thuringia at Eschwege first and then moved on to Franconian Hersfeld further into southern Germany. But he found hardly any support among the princes of the Empire, who were not willing to go to battle with him against the Saxons.

As a result, on 27 January 1074, Henry stood at the head of what was only a small army compared to the much larger Saxon one at Hersfeld. Both sides were afraid to join in battle, but for different reasons. Henry probably because of his obvious inferiority. The Saxon leaders, by contrast, were aware that a victory by their army, consisting mainly of peasants, would have strengthened the position of the latter, something they were not in favour of. So it happened that on 2 February 1074 peace negotiations in Gerstungen took place, which resulted in a settlement between the warring parties. The main outcome was that Henry IV agreed to the slighting of his castles on the edge of the Harz.

Henry's accession to the demolition of his Harz castles included the Harzburg, which included a collegiate church and a family grave containing Henry's dead son and brother. To protect the royal burial ground, Henry directed that only the towers and walls of the Harzburg would be removed. This enraged the surrounding rural population who, in March 1074, razed the castle and its church to their foundation walls and desecrated the royal tombs. This deed may have had a considerable personal effect on Henry, but politically it put all the trumps in his hand: the plunder of the church and the desecration of the royal tomb caused great outrage in his kingdom, and many Imperial princes returned to Henry's side. The Saxon nobility refused any blame for the actions of the rural population and immediately offered to restore the castle and church at their own expense.

First Battle of Langensalza
Henry was once again bent on confrontation and this time gathered a much larger army, although he was not able to march against Saxony until 1075. In the First Battle of Langensalza (known in Germany as the "Battle of Homburg on the Unstrut", Homburg being a former monastery near Bad Langensalza) on 9 June 1075 he dealt the Saxon army, which consisted mainly of simple peasants, a crushing defeat and then rampaged through Saxony and Thuringia laying waste.

Amongst the followers of King Henry who fought with him were the Swabian duke Rudolf of Rheinfelden, Duke Vratislaus II of Bohemia, Duke Theoderic II of Upper Lorraine and the Babenberg margrave Ernest of Austria, who was killed in battle, as well as Bishop Hermann of Bamberg and Count Hermann II of Gleiberg. On the Saxon side, in addition to Count Otto of Northeim and Bishop Burchard II von Halberstadt, were Magnus Billung, meanwhile Duke of Saxony, Margrave Lothair Udo II of the Nordmark and Count Gebhard of Supplinburg, who was killed in battle, as well as the Saxon count palatine Frederick II of Goseck and Count Dietrich II of Katlenburg.

One of the two leaders, Bishop Burchard II of Halberstadt, was detained in Homburg by royal troops and finally handed over on 13 June to the Bishop of Bamberg as a prisoner.

The chronicler Lambert of Hersfeld described the battle in his Annals:

On 27 October at the village of Spier near Sondershausen, the Saxon leader finally capitulated to the king in public, i.e. in front of the whole army. Henry had no mercy, but savoured his triumph. The Saxon leader's submission was barefoot, according to Lambert, and the surrender, without exception, unconditional. Henry then held numerous Saxon princes in prison in various places and transferred their fiefs to others.

Aftermath
Beginning almost simultaneously with the surrender, the Investiture Controversy took Henry's full attention in the years that followed. Unrest in Saxony also flared up during this period again and again, but did not reach the same level of political and military as in the time from 1073 to 1075.

At the diet of princes in Trebur in October 1076, Otto of Northeim again aligned himself with the opposition. Although he was always a potential candidate, the princes did not choose him; instead, in 1077 in Forchheim, they selected Rudolf of Rheinfelden and, later, Hermann of Salm as antikings. Nevertheless, Otto's had a significant influence on the opposition's politics. Militarily, he distinguished himself again in the battles of Mellrichstadt, Flarchheim and the Elster, leading from the front.

Even Henry's son, King Henry V of Germany, still had to fight the Saxons. He lost, for example, the 1115 Battle of Welfesholz to the Saxons led by his later successor, King Lothair III.