Scientific member of the Max Planck Society and director at the Kunsthistorisches Institute in Florenz (since 2003). He received his PhD degree in art history from the University of Heidelberg 1989, and completed his habilitation in Berlin in 1994. He held the chair of art history at Trier University from 1998 to 2003. His numerous guest professorships took him to Paris (EHESS), to Rome (Bibliotheca Hertziana), Vienna, Basel, Buenos Aires, Mexico City, Jerusalem, Mendrisio, Harvard University, Lugano, Chicago University, Istanbul (Boğaziçi University), Delhi (Jawaharlal Nehru University), Zurich (Heinrich Wölfflin Lectures) and New York (Columbia University) Since 2009, he has been a member of the Berlin-Brandenburg Academy of Sciences and Humanities. He was honorary professor at Humboldt University Berlin from 2008 to 2020 and a member of the Scientific Commission of the (German Council of Science and Humanities) from 2013 to 2019.