The Surface Buildings
My reconstruction shows here the staircase and set of five buildings which stand against the cliff. The buildings are bounded on the south side by a set of stairs to an upper level. The orientation of the forecourt and two baths in front of the painted room suggests that this formed part of the original complex. On the north side the buildings are bounded by what was once an arch leading to steps down to a lower level. Paget called these buildings, together with the flat area in front them and the forecourt the ‘Sacred Area’.
This set of buildings today are called ‘Le Piccole Terme, the small baths. They were extensively repurposed by the Romans into a set of baths. It is possible that temple area, with its tunnel entrances, was closed off and served no purpose in the bath complex although here too extensive Roman repairs of various dates are visible. There is a Roman pipe which sits in the antrum trench and doubles back into the Tholos, which had been converted into a Roman sweat room, a sudatorium. In this way hot steam was pumped in from the surface, not from deep within the ancient tunnels.
The buildings in the foreground set at a different angle are all later Roman additions.
We know for certain that the buildings against the cliff were built on a platform hewn out of solid rock and not on top of any previous construction.
The red asterisks indicate where at some point in history someone has broken through a wall, presumably hunting for treasure. There is a break in the bath of Big D which led to the discovery of the hidden staircase behind the niche.
There is a rough break between tanks 1 and 2, which at present is the only known access to tank 2.
There is a break in the curved passage behind the Tholos at the base of Tank 1. Someone clearly broke in here from the curved passage, as the débris mostly lies in the curved passage, not in the tank.
Paget’s sketch of the surface building area
At the back of the temple there is a passage. According to Paget it is blocked a short distance into the hill, but if extended Paget calculated that the direction is such that it would meet the main antrum tunnel at a point where the tunnel from the back of the Tholos also meets the main tunnel, but situated above it.
There is a square Roman tile set in the roof of the main antrum tunnel at this point which should be visible in the floor of the Temple passage. The tile has not been removed and remains in situ.
The Grotto is a feature directly above, and supported by, the vaults of the narrow antrum tunnel below it. Its cross section is similar in shape and size to that of the nearby Oracle of the Sybil at Cuma, suggesting the dates of construction might be similar, which in turn reinforces the Greek, rather than Roman, origins of these tunnels.
The southern passage
From the main entrance tunnel under the Grotto there is a passage leading off to the south. It is blocked a short way in and has not to date been investigated, so little more can be said about it.
Paget suspected this was the original entrance into the main tunnel. His belief was that there had been successive seismic events that had, over the years, caused the cliff face to bury the previous cliff faces. There seem to have been two major events, resulting in an original cliff face that was behind the The Tholos and in line with the North Tank.
This is marked on Paget’s diagram further up this page as the ‘Ancient Cliff’. A similar event caused a further cliff crossing the centre of where the Tholos lies. This is the line of the present day cliff on the upper level.
Where this entrance tunnel meets the main tunnel and masonry gives way to solid volcanic tufa, the edges are rounded off neatly, as if this was once a visible entry into the cliff, hence Paget calling it The Original Entrance.
Because the main tunnel’s axis is on the spring equinox line to Vesuvius where the sun would rise dramatically on this date, I suspect that it too was part of the original concept.
The stairs are hidden directly behind the niche to the left of the ‘Big D’ bath. Paget entered through a hole in the bath itself, dug by others at a date unknown, but it it is most likely to have been either before the site was buried deeply in 79 ad, or after it was excavated around 1956-58. Between those years the site was buried in volcanic ash with vines growing above it.
The staircase is blocked at the top, but there is evidence of a blocked doorway to the right. It is presumed this is linked in some way with the North Tank, as no original entrance to that has so far been found.
There was probably a separate passage leading to this staircase, isolated by a wall from Big D. We can see plaster lines between the two where a wall once protruded from the cliff.
The South tank is entered by a short passage on the level above. Inside the tank there is a platform about 7 feet or 2.13 metres with steps leading to its floor. To the right of the platform is a rough break into the North Tank, so we must presume treasure hunters have made this hole.
There is a small hole at floor level connecting the two tanks. This is not large enough for a person to crawl through but was presumably to allow liquid or gas of some kind to flow through.
To the south end of this tank there is again a treasure-hunter’s break. The person entered from a curved tunnel to the south, leaving his excavations in the curved tunnel. How he entered that tunnel is not known, as it is blocked today, with no other known way in.
The North tunnel seems to have been part of the original plan. It is in exact line with northern line and orientation of the painted room which extends today in front of the cliff face. There is a considerable gap between the painted room and the tank, but after much exploration Paget felt that there is no secret room to be found in between the two. The painted room was found to have a false partition in front of it, which has since been removed to reveal a deliberately defaced painting that appears to have been scoured in some way.
The entrance was probably directly behind where the ancient cliff line once sat, with an entrance directly into this tank room. The staircase is possibly a later means of access.
The foreground extension
There is an extension of the main antrum passage into the hill which extends forward, yet still under the ground, to exit into a room now situated in the Roman buildings. The wall of the building is cut off to the same angle as the tunnel. Paget suggested that this extension, which is angled 5º differently to the main antrum, on a bearing of 275º, was a later addition and perhaps related to some revival of the oracle in Roman times.
This extension is about 0.9 metres (1 yard) wide and meets the main antrum at about 1.8 metres (6 feet) from the north west corner of the temple, at which point it narrows to just 0.5 metres (21 inches) wide and changes bearing to 270º. It is from this point that Paget took his measurements into the hill.