Side view of the mausoleum at the Palace of Diocletian, 1764
Robert Adam was anxious to prove to the aristocracy of Great Britain that he was a bona-fide antiquarian as well as a talented architect. This was done at that time by studying, documenting, and publishing sumptious engraved folios describing archaeological sites. During his stay in Rome, he discovered that the ruins of a late Roman palace was still undocumented. He hired a team of artists, and traveled to the city of Spalato (present-day Split) on the eastern Adriatic coast (present-day Croatia). He and his team spent 5 weeks there, and the results were published in 1764 as The Ruins of the Palace of the Emperor Diocletian at Spalatro in Dalmatia.
Adam erroneously identified the Palace of Diocletian's mausoleum as a Temple of Jupiter. In this side view, the current state of the structure is documented - plants growing from it, contemporary houses next to it, local residents conducting their daily business in its precincts.