The Art Archive/Musée du Louvre, Paris

In early March, Roberts reached Petra, an ancient Nabatean City in southwest Jordan. He described “temples, public buildings, triumphal arches and bridges”— and he painted the so-called Royal Tombs (shown here). Stunned by Petra beauty, Roberts rhapsodically observed that the “air is perfumed with the most delicious fragrance.” Petra’s vast wealth was generated by trade in spices during the first half of the first millennium A.D.