The bishopric's boundaries originally reached the Elbe and Saale rivers in the east, nevertheless, when Emperor Otto I founded the Archbishopric of Magdeburg in 968, Halberstadt lost the eastern half of its district to it.

However the former favourite of Dowager Empress Agnes of Poitou and her son Henry IV in 1073 allied with Pope Gregory VII in the Investiture Controversy and became one of the leading figures of the Great Saxon Revolt.

After the deposition of the Saxon duke Henry the Lion the episcopal and capitular temporalities forming the Stift of Halberstadt evolved to an Imperial State, the prince-bishopric.

Taking full part in the diversion of the Crusade from its mission and the atrocious subsequent sack of Constantinople, Conrad enriched the Prince-Bishopric with many relics and other booty personally looted from the churches, convents, and monasteries of the Roman Imperial capital.

After the foundation of the ancient Archbishopric of Magdeburg, the Diocese of Halberstadt covered the following Saxon Gau counties: Balsamgau, Derlingau, the western part of the Nordthüringgau, Harzgau, Schwabengau, and Hassegau.

The city of Brunswick, located on both sides of the Oker, was originally split between Halberstadt and Hildesheim until it passed to Duke Henry the Lion in 1142, who made it his residence.