That is really a once-in-a-lifetime chain. It certainly belongs to a German, most likely Prussian. We can rule out Schmidt and Hittorf. Judging from the Internet list of Royal Gold medal winners, there are only two candidates: - Friedrich August St?ler AND - Karl Richard Lepsius (1810-1884), very prominent archaeologist. He got the Royal Gold medal in 1869 and the PLM in 1872. Both were Protestants, so I think they would only have got the Vatican order if there were a special reason for it. My feeling is that this is rather the case for Lepsius, because he was apparently president of the German Archaeological Institute in Rome from 1867?1880. He travelled both to Rome and Paris a number of times. Also, I think St?ler would have had even more Prussian (esp. dynastic) awards, because he had very close connections to the Prussian king, having designed the rebuilding of the Hohenzollern castle in Hechingen, for example.