Voynich Comparator | De Balneis Puteolanis: When Healing Water, Naked Bodies and Place Became a Medical Image System

There is a moment in Voynich research when the bathing pages begin to pull too hard.

Naked bodies.

Green water.

Pools.

Tubes.

Architectural forms.

The temptation is to find one medieval bathing manuscript and declare the problem solved.

De Balneis Puteolanis is exactly the manuscript tradition that forces us to become more disciplined.

Written by Peter of Eboli around the turn of the thirteenth century, the poem describes the therapeutic mineral and volcanic baths of the Phlegraean Fields around Pozzuoli and Baia, west of Naples. Individual sections describe named baths and the ailments their waters were believed to treat. Many surviving witnesses are illustrated with bathers, pools, buildings, caves, flowing or steaming water and the physical landscape in which the cure takes place.

It is a genuine medieval medical image system built around bodies in water.

That makes it one of the best possible controls for the Voynich bathing pages.

It also makes it dangerous.

De Balneis Puteolanis proves that medieval therapeutic knowledge could be organised around naked bodies, pools, water systems and named baths. It does not prove that the Voynich bathing pages describe Pozzuoli, balneology or the same medical tradition.

Quick Read

Peter of Eboli composed De Balneis Puteolanis around the beginning of the thirteenth century.
The work describes the therapeutic waters and baths of the Phlegraean Fields around Pozzuoli and Baia in southern Italy.
Individual sections are organised around named baths and their medical properties.
The manuscript tradition is unusually rich in images of bathers, pools, buildings, caves and water.
Biblissima records BnF Latin 8161 as a mid-fourteenth-century witness and notes an extensive southern Italian manuscript tradition.
BnF Français 1313, dated 1392, contains numerous bathing miniatures and provides a late-fourteenth-century visual control very close in time to the Voynich parchment window.
Later fifteenth-century witnesses show that the visual programme continued to be recopied and transformed.
The order and number of baths can vary among manuscripts, demonstrating transmission rather than one frozen layout.
Water, nakedness and architecture can be functional medical information rather than erotic, allegorical or anatomical imagery.
None of this identifies the Voynich bathing pages as De Balneis descendants.

Comparator Firewall

Bathing resemblance ≠ shared text. Shared medical use of water ≠ shared provenance. Southern Italian balneology ≠ Padua. A real source claim requires specific transmitted structure, not a common scene type.

This comparator enters the Voynich programme to do one job:

establish the historical design space for medical bathing imagery.

The Medical Unit Is the Bath, Not the Body

This is the first major difference from many modern readings of the Voynich bathing pages.

In De Balneis, the naked figure is not usually the primary information object.

The bath is.

A named location has particular water.

The water has properties.

Those properties act on illnesses or bodily conditions.

The human figure demonstrates use.

This reverses a common interpretive habit.

If we see a body, we ask what body part it represents.

A balneological manuscript asks instead:

What is the patient doing inside this therapeutic environment?

That is a much wider hypothesis class.

The Water Is Not Background

In ordinary painting, water may be scenery.

In a thermal medical manuscript, water is the active medium.

Its heat, mineral character, location and mode of use are what make the place medically interesting.

The poem itself describes effects attributed to different baths: conditions of the skin, nerves, digestion, fertility, pain, humoral imbalance and other illnesses are associated with particular waters in the tradition.

This creates a useful control for the Voynich green pools.

Water can be the treatment.

Therefore “body in pool” need not encode internal anatomy.

But it also need not encode medicine at all.

The comparator expands possibility without selecting the answer.

Place Is Part of the Therapy

De Balneis is geographically anchored.

It celebrates real thermal sites in the volcanic landscape around Pozzuoli.

The medical system therefore contains an implicit relational graph:

place → spring/bath → water properties → mode of bathing → bodily effect

This is different from an abstract pharmacopoeia.

The treatment cannot be fully separated from the location that produces the water.

That gives Voynich research a testable question.

If the bathing pages encode named therapeutic places, should we expect repeated visual units corresponding to site, treatment and condition?

Do labels behave like toponyms?

Do the same labels recur where the same visual facility recurs?

Does page order behave like an itinerary, catalogue of baths or regimen?

Those predictions are much better than simply saying “this looks like a spa.”

The Pictures Carry Architecture Because Baths Have Architecture

Bathing is spatial.

A thermal site may have a basin, enclosed chamber, cave, pool, access point, channel or built structure.

The illustrated De Balneis tradition therefore often depicts buildings and containment structures together with bathers.

This is useful for the Voynich tube problem.

A tube-like form beside a body can be:

an anatomical vessel;
a hydraulic channel;
a symbolic connector;
a decorative border;
a container;
a spatial abstraction of architecture;
or something else entirely.

A balneological control prevents anatomy from becoming the default simply because bodies are present.

Nakedness Can Be Operational

The bathers in De Balneis are frequently nude because bathing requires the body to be exposed to water, steam or heat.

The nakedness is therefore functional.

This gives us another important negative control.

Nudity in a medieval manuscript does not automatically imply sexuality, childbirth, anatomy or allegory.

It can indicate treatment.

At the same time, the Voynich figures have their own peculiar visual grammar: predominantly female-presenting bodies, repeated small figures, elaborate conduits and often highly abstracted spaces.

Those differences matter.

A good comparator keeps both resemblance and divergence visible.

The Manuscript Tradition Itself Is a Transmission Experiment

The work survives in many manuscripts across the thirteenth to fifteenth centuries, with different textual and visual states.

Cambridge scholarship notes that the poem can contain descriptions of up to thirty-seven baths and that the ordering varies among witnesses.

Biblissima notes around twenty southern Italian copies in the relevant medieval period for the BnF tradition, while broader scholarship counts additional witnesses, translations and later printed transmission.

This is extremely useful.

We can observe what a known bathing-information lineage does under copying.

Which scenes stay recognisable?

Which baths change order?

Which architectural motifs survive?

How much freedom do illuminators take?

Those empirical transformation rates can then discipline Voynich source claims.

BnF Latin 8161 Gives Us a Mid-Fourteenth-Century State

Biblissima and the BnF identify Latin 8161 as a mid-fourteenth-century manuscript of Peter of Eboli’s work.

Its images include named baths such as the bath called Sol et Luna, the Spelunca and others in the Pozzuoli/Baia environment.

This state matters because it preserves a visual tradition already at least a century old.

The manuscript is not a fresh observation notebook of fourteenth-century baths.

Its image conventions are partly inherited.

Biblissima explicitly notes archaic scene arrangements explained by descent from an earlier model.

This is a direct warning for Voynich.

An image can look older than its parchment because the image tradition is older than the copy.

BnF Français 1313 Gives Us a 1392 Control

Français 1313 is especially useful because Biblissima dates its bathing miniatures to 1392.

That places a richly illustrated bathing manuscript immediately before the Voynich parchment range.

Again, temporal adjacency is not genealogy.

But it gives us a precise control for what a late-fourteenth-century manuscript could do with thermal medicine and the human body.

Any claim that the Voynich bathing imagery is impossible or unprecedented in medieval medical culture therefore fails.

The real question moves to the differences.

The Major Voynich Difference: The Baths Are Not Named in Readable Language

De Balneis is interpretable because text and image lock together.

A rubric names a bath.

The verse describes its properties.

The image depicts the therapeutic place.

The Voynich lacks this secure Rosetta relationship.

Its labels are unread.

Its pools are not tied to documented geography.

Its pipes or conduits have no agreed function.

Therefore visual similarity cannot import De Balneis semantics into Voynichese.

A Balneological Hypothesis Should Produce Specific Predictions

If the Voynich biological/bathing material is genuinely balneological, a serious theory should predict more than bodies in water.

Repeated visual units should correspond to repeated treatment types, facilities or water properties.
Labels should cluster as names, conditions, directions or properties rather than arbitrary prose.
Page order may preserve a catalogue, route, site sequence or therapeutic logic.
Different pools should correlate with different bodily actions or conditions.
Architecture should behave spatially rather than anatomically.
Water or conduit networks should have consistent directionality.
Related historical balneological manuscripts should provide better structural matches than unrelated naked-figure manuscripts.

A theory that cannot make these predictions is not yet a balneological model.

It is a visual association.

The Padua Hypothesis Must Keep This Comparator Outside Its Provenance Lane

This is especially important because our Padua work has already examined Abano and the Euganean thermal landscape.

There is now a temptation to combine:

Voynich bathers;
Abano thermal medicine;
Peter of Eboli bathing manuscripts;
northern Italian medical networks;
the Voynich parchment window.

That would create a beautiful story.

It would still not create provenance.

De Balneis Puteolanis is rooted in Campania and the Phlegraean Fields, not Padua.

Its relevance to Padua is comparative: balneological medicine was a real knowledge domain with its own visual possibilities.

That is all we are entitled to transfer without independent evidence.

What De Balneis Can Legitimately Teach Voynich Research

Naked bodies in pools can be functional medical imagery.
Water can be an active therapeutic substance rather than scenery.
Bath architecture and landscape can be part of the medical information.
A medical manuscript can organise knowledge by named therapeutic places.
Bathing imagery existed in rich manuscript traditions before the Voynich parchment was made.
An inherited image tradition can preserve archaic-looking arrangements in later copies.
Known manuscript families can be used to measure how bathing images transform through copying.
Balneology should be tested as a structured hypothesis, not invoked as a resemblance.

What It Does Not Prove

that Voynich depicts Pozzuoli or Baia;
that Voynich derives from Peter of Eboli;
that Voynich bathing pages are a spa guide;
that the green pools are mineral baths;
that the tubes are hydraulic pipes;
that Abano or Padua becomes more likely simply because thermal medicine existed elsewhere in Italy;
that female-presenting Voynich figures have the same role as De Balneis bathers;
that visual resemblance transfers textual meaning.

The eduKate Bathing-Image Test

Build a census of illustrated De Balneis witnesses from the thirteenth to fifteenth centuries.
Segment every scene into body, water, architecture, landscape and text-label components.
Align named baths across witnesses.
Measure which visual features survive copying.
Measure how often order changes.
Identify motifs common across the whole bathing genre.
Downweight those generic motifs in Voynich comparison.
Identify rare structural correspondences that would have genealogical value.
Compare Voynich bathing pages blind to manuscript identity.
Reject any proposed source relation that requires more transformation freedom than the known De Balneis family itself displays.

Student Lens: A Body in Water Can Mean a System

Primary: compare a swimming-pool picture with a hospital-treatment picture. The same body-in-water geometry can have different functions.

Lower Secondary: separate the patient, treatment, place and outcome in a historical medical scene.

Upper Secondary: test whether visual resemblance predicts shared function by using controls from unrelated bathing imagery.

JC and adult readers: model a manuscript image as a relational graph rather than a picture: site, medium, user, treatment, indication and result can all be encoded by one scene.

Research Sources

Continue the Comparator Route

The Final Idea

De Balneis Puteolanis does not make the Voynich bathing pages less strange.

It makes the strangeness more precise.

Medieval medicine already knew how to draw naked patients in therapeutic water.

It already knew how to connect bodies to pools, caves, buildings and place.

So none of those features alone can carry the explanatory burden.

What remains to explain is the Voynich-specific organisation:

its repeated small figures, its conduits, its green pools, its unread labels, its page grammar and its relationship to the rest of the manuscript.

A good bathing comparator removes the generic medieval features first. Only then can we see what the Voynich bathing system actually needs us to explain.