has been working on a biography of Antipope Boniface VII. He published numerous individual studies on him. After decades of research, the first volume of the biography with the three chapters "Youth and ecclesiastical consecration", "On the way to the papal throne" and "Election to the pope, consecration and coronation" could be published in 2015 in the series "Popes and Papacy". The challenge was above all to prepare the time appropriately historiographically. Numerous details about his early life are not contemporary testimonies, but were only reproached to him in the later Boniface trial. Since the 1990s, the Upper Silesian-born Herde has also devoted itself to Silesian history. In 2001, the edition of the Italian files on the 1921 referendum in Upper Silesia resulted from this occupation. At the end of the century Herde was more intensively engaged in the history of historical studies. This resulted in numerous studies on Würzburg historians such as Anton Chroust (1998/2012), Max Buchner (2002) and Michael Seidlmayer (2007/2012). Herde investigated the background of the failed appeals of Franz Schnabel to Heidelberg and Hermann Heimpel to Munich. Herde thoroughly evaluated the files of the American military government. Together with the Israeli historian Benjamin Z. Kedar, he presented an investigation of the historian Karl Bosl in 2011, which led to a discussion and reassessment of Bosl's Nazi past. The German translation was published in a substantially extended version in 2016. At Bosl, they observed "a precarious coexistence of rejection and concessions" with the system. According to their research, Bosl had behaved in a highly system-compliant manner under National Socialism and falsely presented himself as a resistance fighter. Some historians criticized the depiction of Kedar and Herde and pointed out discrepancies. Dirk Walter criticised the lack of comparison of Bosl's career during the Nazi era with that of other colleagues like Theodor Schieder. Herde presented numerous works on the history of the Second World War, including two monographs on the secret flight connection between the Axis Powers and Japan ('The Flight to Japan', 2000) and on Japanese occupation policy in Southeast Asia during the Second World War and its consequences ('Greater East Asian Prosperity Sphere', 2002). However, he only dealt with Indonesia and the Philippines and did not use Japanese sources for his account. Herde noted in his study that "despite all controls and despite censorship [...] Japanese rule [...] in the Philippines was not totalitarianism of a