Keller, Hagen

Ruedi Hagen Keller (born 2 May 1937, in Freiburg im Breisgau, Germany) is a German historian specializing in the history of the early and high Middle Ages. He works mainly on the Ottonian period, the Italian communes, and the culture of writing in the Middle Ages. Keller taught as Professor of Medieval History at the University of Münster from 1982 until his retirement in 2002. His collaboration with his colleague Gerd Althoff was particularly fruitful. With their work, Keller and Althoff made a decisive contribution to Münster's reputation in international medieval studies. Keller's research has had a considerable influence on German and international medieval studies since the 1980s and has led to a reassessment of early and high medieval kingship.