Since the summer semester 2004, he has obtained a professorship for Classical Philology and Papyrology at the Institute for Prehistoric Studies of the University of Cologne. 2000-2004: teaching position in Greek in Jena. He also helped to establish the project of a joint, Internet-based development of the papyrus collections of Jena-Halle-Leipzig, sponsored by the DFG (German Research Foundation). Member of the following committees: “Griechische christliche Schriftsteller” of the Berlin-Brandenburg Academy of Science and “Centro Internazionale per lo Studio dei Papiri Ercolanesi”, University of Naples. Joint publisher of the journal "Zeitschrift für Papyrologie und Epigraphik."