ROME — The ancient Pompeian fresco depicting the mythological scene of Leda and the swan was well preserved. It shows the rape of the queen of Sparta by Jupiter, the Romans’ Zeus, in the form of a swan.

The archaeological treasure, unearthed this month in the bedroom of a house being excavated on the Via del Vesuvio in Pompeii, was the latest find from an extensive excavation campaign to secure some of the fragile archaeological site’s most at-risk areas.

“This is one of the most critical areas of Pompeii,” Massimo Osanna, the site’s director general, said in a video, which shows an archaeologist carefully brushing centuries of earth from the Leda fresco, which was buried — along with the rest of the city — under ash, lapilli and rubble when Vesuvius erupted in 79 A.D.

The recovery of the house is part of a large-scale intervention, known as the Great Pompeii Project, in the Regio V sector of the city, begun in July 2017 with funds from the European Union.