He attended lectures by philosophers Friedrich Adolf Trendelenburg and Karl Werder, philologists August Boeckh, Carl Eduard Geppert, Moriz Haupt, and Martin Hertz, historians Ernst Curtius, Siegfried Hirsch, Rudolf Köpke, Leopold von Ranke, and Wilhelm Wattenbach, Germanists Friedrich von der Hagen and Hans Ferdinand Maßmann, legal scholars Heinrich Eduard Dirksen, Rudolf von Gneist, Adolf Helfferich, and Carl Gustav Homeyer, as well as geographer Carl Ritter.
[2] He devoted himself to the unfinished work of Heinrich Wilhelm Schulz on the medieval art monuments of Southern Italy and assisted Ferdinand von Quast in its publication.
However, his name was missing from the title page of the work, which was published in Easter 1860 and to which he had devoted his youthful enthusiasm during the years 1856-1860: Denkmäler der Kunst des Mittelalters in Unteritalien von Heinrich Wilhelm Schulz.
After an unsuccessful convalescent leave at Lake Geneva, he was sent to the archives of the Foreign Ministry in 1864, where he found his main task as cataloger of the Teutonic Order sources.
In Volume 3, the newly discovered Thorner Annals, along with the chronicle by Johann von Posilge and Detmar's 'Lübische Chronik', are published.