It should not be confused with the larger Diocese of Brandenburg (Latin: Dioecesis Brandenburgensis) established by King Otto I of Germany in 948, in the territory of the Marca Geronis (Saxon Eastern March) east of the Elbe river.

The Prince-Bishopric of Brandenburg was an imperial estate of the Holy Roman Empire for some time, probably starting about 1161/1165.

As rulers of imperial immediacy, regnant in a, however, dispersed territory partitioned into the four bailiwicks (German: Ämter) of Brandenburg/Havel, Ketzin, Teltow and Ziesar.

The last actual bishop was Matthias von Jagow (d. 1544), who took the side of the Protestant Reformation, married, and in every way furthered the undertakings of the Hohenzollern elector Joachim II.

There were two more nominal bishops, but on the petition of the latter of these, the electoral prince John George of Brandenburg appointed in 1560, the secularisation of the bishopric was undertaken and finally accomplished in 1571, in spite of legal proceedings to reassert the imperial immediacy of the prince-bishopric within the Empire and so to likewise preserve the diocese, which dragged on into the 17th century.