Théodule Devéria help Mariette read inscriptions in Cairo and its surroundings. He tried to accurately document the archaeological sites using drawings, stampings and photographs. His calotype pictures from this trip are often poor in quality, showing a lack of technical skills. In 1860 he was appointed preserving assistant at the Louvre's Department of Egyptology. He revisited Egypt in 1861–62, traveling up the Nile to Philae at the First Cataract, and into Nubia to the Abu Simbel temples. After returning he helped Mariette prepare descriptions of the excavation in Egypt in 1850–54 for publication. In November 1864 Devéria met the future oriental scholar
Kazimierz Michałowski were discovered under the "church of the columns". The second building based on the cruciform plan was also explored as well as a mosque which turned out to be erected on a former royal palace and not (as previously assumed) on a Christian temple. Polish archaeologists discovered also a baptistery. Since 1966 a Polish mission was performing parallel prehistoric excavations in the vicinity the village of Gaddar. Professor Michałowski did not excavate in Abu Simbel but along with a team of Polish archaeologists he took part in the salvaging of rock temples of Pharaoh Ramesses II, which were at risk