Norbert von Xanten, was the the Lasombra Prince of Brunswick (Braunschweig), Germany, during the Dark Ages. He was a bitter rival of Prince Jürgen von Magdeburg.
Biography
Norbert had once harbored desires of taking Magdeburg, having been its archbishop in life. When he had joined the ranks of the undead, the Brujah Cedric had still been Prince of Magdeburg and Jürgen his occasional advisor (though still in service to Hardestadt).
After a fire claimed Cedric, Norbert and Jürgen had both been contenders for the city’s throne, but with Hardestadt’s support, Jürgen had easily emerged victorious. Eventually, Norbert took the princedom of Braunschweig, becoming a torn on the side of the ruler of Magdenburg.
Trivia
For the real historical character you might check: Norbert of Xanten
References
Dark Ages Clan Novel: Ventrue, p. 36, 46, etc