|Drusus. Source: Cleveland Museum of Art|
It has been announced that the head will be returned to Italy (Steven Litt, "Cleveland Museum of Art returns ancient Roman portrait of Drusus after learning it was stolen from Italy in WWII", cleveland.com April 18, 2017). It is now understood that the portrait was excavated at Sessa Aurunca, Campania in the mid-1920s. It appears that the head was stolen from the museum there around 1944.
This now raises questions about the due diligence process surrounding the acquisition as well as other material handled by the same dealer. The curatorial team will no doubt be releasing the basis of their pre-acquisition enquiries.