Mayer was born in
Nuremberg on 2 February 1932. He was an international expert on the history of the Crusades. He was the Professor of Medieval and Modern History at the
University of Kiel. He was elected to the
American Philosophical Society in 1978. He was honored in the
festschrift Montjoie: studies in Crusade history in honour of Hans Eberhard Mayer (1997). Mayer was a member of the
Monumenta Germaniae Historica between 1956 and 1967. He was a visiting fellow at the
German Historical Institute in Rome in 1961. He was a visiting fellow in 1965 and visiting scholar in 1970 to
Dumbarton Oaks in Washington, D.C., lecturer at the
University of Innsbruck between 1964 and 1967, visiting professor at
Yale University in 1971, and member of the
Institute for Advanced Study in Princeton, New Jersey, between 1972 and 1973. Mayer died in
Klausdorf on 21 October 2023, at the age of 91. ==Works==