It is in equal parts gratifying and extraordinary that Roman Pompeii should still be making headlines 2,000 years after it was destroyed. Now comes news of a discovery there of an extremely opulent ancient ‘dining’ room with stark white mosaic floors and dramatic black walls featuring some of the most exquisite mythological-themed frescoes found so far this century.

Pompeii truly is the gift that keeps on giving. On the one hand, this shouldn’t surprise us, for until a few years ago it was estimated that up to a third of the ancient city remained unexcavated. The catastrophic eruption of Vesuvius, which smothered the Bay of Naples in AD 79, served to seal in many of the splendours that are only now coming to light. On the other hand, we shouldn’t lose sight of how rare it is to be able to examine antique objects and works of art in near-perfect condition in situ – in people’s homes and places of work – when so often we lack the surrounding context of a complete room.

Many will be wondering why so much of Pompeii remains covered over. The newly discovered dining room, which measures roughly 15 x 6 metres, formed part of a villa located in block 10 of Region IX, a previously unexplored area of the city. The short answer is that, by contrast with earlier generations, who went digging over-zealously for anything they could find, today’s archaeologists have had to focus far more on using what funding exists to preserve the parts of the city already exposed to light.

A game-changing 105-million-euro Great Pompeii Project was launched in 2012 to protect the excavated buildings from human and environmental damage, including theft, to consolidate and restore masonry, and to fortify the borders between the excavated and unexcavated sections of the site to reduce hydrogeological risks. The impressive discoveries made in the process of this project nonetheless reveal that archaeologists are steadily chipping away at that mysterious remaining third of Pompeii which remains hidden from us.

The latest wall-paintings to be uncovered are remarkable for their artistry, bright colours and Trojan War-related themes. One shows a diaphanously-draped yet rather serious-looking Helen of Sparta meeting Paris/Alexandros, prince of Troy, for the first time. It was in response to Paris taking Helen that the Greeks launched their assault upon Troy, eventually storming the citadel in the tenth year of the conflict. In another of the paintings, a lyre-brandishing Apollo, god of the arts, comes before Cassandra, also of the Trojan royal family. It was said that Apollo punished Cassandra for rejecting his advances by ensuring that none of her prophecies were ever believed. A further painting shows Leda being ravaged by a swan, who is Zeus/Jupiter in disguise. Helen was among the children who hatched, bird-like, from one of Leda’s eggs following this unorthodox encounter.

The paintings would have looked all the more vibrant against the black walls as light flooded into the dark room from a large opening at one end, which probably led out onto a courtyard. A theory put forward by the archaeologists at Pompeii is that the black paint was used to conceal the soot that would have covered the room from oil lamps. My personal view is that the considerations were less practical than aesthetic. It was not very common to paint rooms entirely black, to judge from what is extant, but black rooms have been found in some of the grandest villas of antiquity, including the ancient villa Farnesina in Rome. The theatricality of sitting in a room with black walls and white floors cannot be underestimated.

It is precisely the sort of décor that might have appealed to the villa’s putative owner, an ambitious politician and man on the make, Aulus Rustius Verus. He has been identified as the owner of the block on which this villa sits based on the discovery of his initials on various items. It is so far impossible to say whether he lived here himself, or let the property to one of his friends or wealthy supporters, but it is highly likely that he dined in the black room on occasion.

The conviviality of this setting contrasts sharply with what was going on behind the walls of this villa. Situated on the same block (Latin: insula) were a launderette, in which slaves washed people’s clothes using urine, among other substances, and a bakery. The bakery, also excavated recently, still has the indentations in its floor to coordinate the monotonous movements of slaves and blindfolded donkeys as they processed the grain. The windows of the room were barred and too high up to see out of. The remains of two women and a young child, crushed by a falling roof during the eruption, have been discovered nearby.

The archaeological developments are important when taken together because they illustrate so clearly the cheek-by-jowl existence of the rich and the poor, the free and the enslaved. What would a slave have made of the frescoes in the black room? One cannot help but wonder who was responsible for the deeply contrasting phallic graffiti and line drawings of gladiators lately found in the stairway of the same house.