An introduction to the Oracle

Plan view of the Oracle within the hillside at Baia

Areas within the hill are marked in red. Some hidden features near the entrance, not directly associated with the tunnels, have been omitted for clarity.

Surface buildings associated with the original function of the oracle are marked in yellow. Other parts of the Roman baths are shown in orange.

The wider extension of the tunnel to the detatched building marked in yellow within the bath complex is possibly part of a later revival, its relationship is uncertain.


The areas of interest here are a set of buildings and features of Greek origin, much later incorporated into set of Roman baths. It is believed they served some ritual purpose, completely unconnected with the Roman baths visible today. There are all the ingredients for a ritual descent into an underworld, as described by Homer, Virgil and many other writers.

Doc Paget’s plans, drawn in the early 1960s

The site is divided between the buildings that are visible above ground and the tunnels and associated features that are buried within the hillside, going 600 feet or 183 metres into the hillside. At the lowest point, just slightly above sea level, is a fresh water river that maintains a constant level, although this has risen and fallen over the last three millennia, the centuries and even within our own lifetimes. The water is drinkable.

The antiquity of the tunnels is indicated by the depth of crystalline deposits on the floor that have reduced the height by about 2 and a half feet, or 0.75 of a metre.

The whole region is highly volcanic, comprised of about 80 craters which look from above like a bubbling, melting, glue pot. The areas above ground have been subject to changes over the centuries due to earthquakes and landslides.

However, while the surface buildings at Baia show signs of many phases of rebuilding and repair, undoubtably necessary due to volcanic activity, the features inside the volcanic hill display no cracks or signs of amendment. While the edges of volcanic craters in the region display dramatic changes over time, with hot springs, geysers, rising and falling land, within the solid crater wall the rock has remained constant and unfractured.

There is evidence that the original cliff was somewhat further back when the buildings were originally built, and we might be forgiven for assuming that landslides have caused the present cliff and buildings to appear less deep than they were originally.

I am not sure whether any repair work was undertaken at Baia between this time and the huge eruption of Vesuvius in 79 AD, but it does appear that some brickwork is Neronian, so this may be the case. It is more likely that Neronian brickwork was built prior to 63 AD. The earthquake produced a massive landslide at the Roman baths at Baia, so the whole area may have been abandoned at this time, 63 AD.

There are pillars strewn around on the ground outside the buildings under discussion here. These have clearly come from above, as they have no bases on this level. Neither are there any bases for these columns on the level directly above. They are for now a mystery, they must have come from higher up, an area not yet excavated.

Visible today at the site

Identification of the surface buildings and features.

This is a general view towards a set of buildings, set against a cliff. They are all that remains of buildings that once projected forward from the cliff. They sit against the cliff wall largely as silhouettes. The Painted Room has been ‘restored’ in the sense of being covered over to preserve the paintings that remain on the walls. We do know that it had a doorway into Big D, because the threshold stone is in place.

Each of these buildings, together with details of what is hidden behind, will be described in detail on their own pages, but for now a brief introduction follows.

The surface buildings – overview

From left to right a staircase and five buildings are set against the cliff. The staircase leads to an upper level which appears to have some features related to the purpose and function of the lower level.

At the lower level, if we face the cliff, are a set of what appear today to be five buildings. I propose to use Paget’s naming of the buildings, as he was first to describe in his book: ‘In the Footsteps of Orpheus – The discovery of the Ancient Greek Underworld’.

The five buildings are:

1] The Greek temple, with a possible small room behind it. The temple has access to a passage in the hillside called The Grotto. Below the temple is a narrow passage leading due west, deep within the hillside. This building may have been sealed off from the rest of the later Roman baths. The small room behind the temple has a passage which is likely to intersect with the narrow passage above, but at a higher level, where a large tile can be seen in the tunnel roof. This passage is currently blocked and has not been investigated.

2] The Original Entrance. probably at one time connected directly with the Greek Temple, it was later converted for use as part of the Roman baths. At the back of the entrance is a steep descent in a passage which leads to the same underground passage.

3] The Sudatorium with an entrance to a beehive Tholos. The Tholos has an opening in its roof, upon which sits a stone ring, still in situ, on the upper level. In the floor of the Tholos is a trench, which again connects with the two tunnels already mentioned

4] Paget called this room Big D, because of the big D-shaped bath set into the cliff. To the left of this bath is a statue alcove. The alcove is a later addition and it seems there may well have been a narrow corridor towards where the niche now is, because there is a double plaster line set into the back wall which suggests there was a wall protruding from it. Behind the niche is a now hidden steep staircase, blocked at the top where there is a doorway to the right. This leads towards two tanks that reside within the hillside, whose purpose is uncertain.

5] The Painted Room. This is a semi-restored room which originally had friezes on the walls, some traces of which still exist, although there are signs of deliberate eradication during Roman times. This building faces a paved court with two D shaped baths at two of its sides, which are oriented to the other buildings and seem part of this arrangement.

Within the crater wall

Temple entranceOriginal EntranceTholos entrance

The three entrances to the Underworldthe Greek Temple, the Original Entrance and the Tholos each have entrances to underground passages that meet at a single tunnel some way into the cliff.

Key features of the tunnels

A single long, dead straight passage continues a gentle descent into the cliff for about 400 feet, 122 metres, before reaching an S bend which obscured the view beyond.

At this point there was a hinged door, probably disguised, which could offer one of two paths, straight on or right.

If the door was swung to the left, the only way was down to the River Styx. Having navigated the Styx, a passage at the back then led up to the Oracle Sanctuary, which sits directly above the underground river.

If the door was swung to the right, a passage to the left led directly to the Oracle Sanctuary. This, presumably, is the route taken by those officiating at whatever event took place. Sacrificial animals were described as being led in behind enquirers to the oracle, so perhaps these mysteriously disappeared via the swing door, to appear again sacrificed once the supplicant emerged from the Styx ordeal.

The current situation is that the Romans blocked off the path to the sanctuary with a thin masonry wall, leaving the path down to the River Styx as the only option and path to take.

Just before the River Styx is an opening to the right, with a curved path that leads around and up, again leading to the Oracle Sanctuary. Paget nicknamed this passage The Rise. All the tunnels appear to have been created and planned as one original unit, except for The Rise, which shows less encrustation and an awkward junction where it meets The Sanctuary. This may be an added later feature.

In addition there are other tunnels and features which will be explained in more details elsewhere on this site. When this site is developed further the features described above and the other known tunnels will appear on sub pages under the menu heading at the top of the page.

The Stairs

The stairs mark the most southernly limit of the buildings and provides access to the associated buildings above.

The Greek Temple

Encased in later Roman masonry, the earlier massive stone blocks of the Greek Temple in a different stone are clearly visible.

The Original Entrance

This entrance to the ancient oracle was concealed behind a wall forming the back of a later small Roman bath.

The discoverer, Robert Paget, believed that this was the original entrance and named it so.

The Tholos

A Tholos typically points to a Mycenaean origin. The example at Baia shows slight distortion presumably from volcanic disturbance.

It has a trench in the floor connecting with the main oracle passage. It was later turned into a sudatorium, a Roman sweat room.

Big D

Big D is now a single room, with a small statue niche next to a large D shaped bath.

Vertical plaster lines in the stonework indicate that a wall once extended from between the niche and the D bath.

It is likely there was a separate corridor here to a staircase which exists behind the niche.

The Painted Room

This room communicated with Big D – there was a doorway between them.

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