At the Archaeological Museum of the University of Halle, the establishment of a collection of copies of ancient wall paintings and images of painted tombstones from the Vesuvius cities of Herculaneum and Pompeii, the Middle Greek Demetrias, and wall paintings from Knossos in Crete began towards the end of the 19th century. These artistic watercolor copies were precise reproductions of the ancient representations, their state of preservation, and their coloration immediately after excavation. From the beginning of the excavations in the 18th century in Herculaneum until the early 20th century, watercolor painting was used as an archaeological documentation form for ancient fresco painting before photography ultimately replaced it. The museum's collection of watercolor copies in Halle, mostly depicting ancient mythological scenes, but also images of the deceased and cultic palace images from Knossos, was primarily established by the archaeologist Carl Robert (director of the museum from 1890 to 1920). Most of the paintings were done by the Swiss artist Émile Gilliéron, who lived in Athens and was a well-known painter, draftsman, and restorer involved in many excavations in Greece. Unlike today's archaeological research interest, which tends to focus more on the intentions of the patron, clues about the artist, and the context, the largely unknown collection of watercolor copies in the Archaeological Museum is an expression and result of an artistic-scientific research process. The catalog documents the study of ancient polychromy during the Art Nouveau period from around 1890 to 1910.