Covid really got in the way of this long-anticipated trip to Pittsburgh. We rescheduled this visit several times and still Covid felled Lisa. With a switch-up of the team - Aaron Shugar, who runs the XRF, accompanied Evonne and Jane on this trip – we managed to make it to the Carnegie Museum of Art. We were really looking forward to studying The Bust of Gregory XV, one of four known casts. We are very familiar with the marble bust of Gregory XV in the Art Gallery of Ontario which has the same round socle as the Carnegie bust. Jane has scanned it and the comparisons are revealing of the distinct engineering challenges of marble versus bronze busts. This was a complex work, full of surprising repairs, a reinforced attachment of bust to base, and… a newly discovered signature and date which we saw only at the end of the day when we tipped the bust to take a look inside the socle. The later date of this bust could well explain why the cast was made so differently from the three others. We appreciated the close collaboration with Aaron’s former student, Mary Wilcop, now conservator at the Carnegie and a visit (on a Saturday no less) by the curator Akemi May. If we are able, we would like to return to take a second look at this still somewhat enigmatic bust with Lisa.