structural:scholar_edition
Consolidation

Pope Gregory VII repeated Henry's excommunication in late 1084, but many of the Pope's former supporters came to pay homage to Henry as emperor at Cologne at Christmas. His supporters and opponents held a joint conference on the river Werra on 20 January 1085 but could not reach a compromise. The Saxon Count Theoderic II of Katlenburg and Bishop Udo of Hildesheim entered into secret negotiations with Henry during the conference, but the Saxons who remained hostile to Henry soon murdered Theoderic and forced the bishop to flee from Saxony. After the bishop persuaded Henry to pledge he would respect the Saxons' liberties, many rebels laid down their arms.

The papal legate, Cardinal Odo of Ostia, summoned the German prelates who were loyal to Pope Gregory VII to a synod at Quedlinburg. The synod issued a decree that papal judgements could not be questioned and forbade the faithful to make contact with those who had been excommunicated. In response, Henry held a general assembly in Mainz in late April or early May. Three or four archbishops and fifteen bishops obeyed his summons. They deposed their peers—two archbishops and thirteen bishops—who had failed to come to Mainz. The synod also established the " Peace of God " in Germany, prohibiting armed conflicts during the main Christian festivals. Vratislaus II of Bohemia, who had always been Henry's loyal supporter, was rewarded with the title of king during this meeting.

Pope Gregory VII died in Salerno on 25 May 1085. Henry exploited his most prominent opponent's death to consolidate his position. Henry visited Lower Lorraine to end a conflict between his two supporters, Bishops Theoderic of Verdun and Henry of Liège in June 1085. He granted the County of Verdun to Henry of Liège's kinsman, Godfrey of Bouillon, and compensated Bishop Theoderic with estates confiscated from Matilda of Tuscany. Peace was not restored, however, because Godfrey of Bouillon soon laid claim to Matilda's estates. Henry invaded Saxony, reaching as far as Magdeburg in July. Hermann of Salm, Hartwig, Archbishop of Magdeburg and the archbishop's three suffragans fled to Denmark and the Saxons paid homage to Henry. Henry did not restore the rebels' confiscated estates and appointed new officials. The Saxons rose up in a new rebellion and forced Henry to withdraw to Franconia. Henry mustered a new army and invaded Saxony in January 1086, but the Saxons avoided a pitched battle. Henry withdrew to Regensburg. Welf of Bavaria laid siege to the town at Easter, but Henry was relieved by his supporters.

Henry's Bavarian, Swabian and Saxon opponents laid siege to Würzburg in July 1086, because possession of the town could secure their uninterrupted communication. Henry decided to force them to abandon the siege, but the rebels routed his army in the Battle of Pleichfeld on 11 August. Henry launched a military campaign against his enemies in Bavaria. In an attempt to restore peace, Bavarian and Swabian aristocrats from both kings' camps held a joint conference in Oppenheim in February 1087. Henry did not attend. He went to Aachen where his son, Conrad, was crowned his co-ruler on 30 May. On this occasion Henry likely rewarded Godfrey of Bouillon with the Duchy of Lower Lorraine.

A new joint conference of the German prelates and aristocrats assembled at Speyer in August 1087. Henry's opponents were willing to pay homage to him provided he had been absolved by the Pope. Henry refused them, maintaining he had been unlawfully excommunicated. Pope Gregory VII's successor, Pope Victor III, held a synod in Benevento around the same time. The synod passed no resolution about Henry, suggesting the new Pope had adopted a conciliatory policy.

A sudden illness prevented Henry from invading Saxony in October. After his recovery he launched a military expedition against the Saxon rebels. One of the rebel leaders, Egbert II of Brunswick, began to negotiate his surrender. Henry offered him the Margravate of Meissen, but Egbert decided to continue the fight against Henry after two Saxon prelates, Hartwig of Magdeburg and Burchard of Halberstadt, promised to achieve his election as king of Germany. The two prelates could not keep their promise, and Egbert swore fealty to Henry in early 1088. Egbert's about-face and Burchard's unexpected death on 7 April 1088 accelerated the disintegration of the Saxon rebels' camp. Hartwig of Magdeburg and his suffragans hurried to pay homage to Henry, and were followed to Henry's court by prominent Saxon aristocrats. Henry appointed Hartwig to be his lieutenant in Saxony.

Abandoned by his principal allies, the ailing Hermann of Salm sought Henry's permission to leave Saxony for his native Lorraine. His request was granted and he died in his homeland on 28 September 1088. Egbert of Brunswick rose up in a new rebellion and defeated Henry's army near Gleichen on 25 December. Egbert's estates were confiscated in February 1089. Henry, who had been widowed, went to Cologne to celebrate a new marriage with Eupraxia of Kiev in the summer of 1089. In the autumn, Henry returned to Saxony to prevent Egbert from attacking Hildesheim, but he continued to resist.