Voynich Comparator | Getty Ms. Ludwig XII 7: The Volvelle That Turned a Manuscript Page Into a Calculator

A medieval diagram does not have to sit still.

Sometimes the reader turns it.

Getty Museum Ms. Ludwig XII 7 contains one of the most useful controls for understanding that difference.

The manuscript is an English astronomical and medical miscellany made in the late fourteenth century, shortly after 1386, probably in Oxford or Worcester. It includes constellation tables, astronomical material, medical prognostication and other learned texts.

On folio 51, the manuscript contains an astronomical volvelle: a movable circular device made from layered parchment components attached at the centre so that parts can rotate relative to one another.

The page is no longer merely something to read.

It becomes something to operate.

Getty Ms. Ludwig XII 7 is a powerful Voynich control because it proves that medieval manuscript geometry could be executable: the reader could manipulate a diagram to generate or retrieve astronomical information.

Quick Read

The J. Paul Getty Museum identifies Ms. Ludwig XII 7 as an English astronomical and medical miscellany.
It was made shortly after 1386, probably in Oxford or Worcester.
The manuscript includes astronomical tables, constellation material and medical/prognostic texts.
Its intellectual sources include Robert Grosseteste, Hippocrates, Nicholas of Lynn, William Reade and translated learned traditions.
Folio 51 contains an astronomical volvelle.
A volvelle uses movable circular elements to model or calculate relationships.
Getty’s interpretation explains the device as a manipulable astronomical instrument for relating the Sun, Moon and dates.
The device shows that physical interaction can be part of manuscript meaning.
This is a pre-Voynich control: interactive diagramming existed before the Voynich parchment was produced.
It does not prove any Voynich circular diagram once had missing moving parts.

Comparator Firewall

Movable circle ≠ Voynich circle. Pre-1400 Oxford astronomy ≠ Voynich provenance. The volvelle establishes an interaction mechanism, not a genealogy.

The Diagram Is a Small Machine

A static diagram presents one state.

A movable diagram can represent many states.

Rotate one component.

A relationship changes.

Rotate another.

A new configuration becomes visible.

The reader is effectively executing a model.

This is an important conceptual shift for Voynich research.

A circular manuscript page may be:

an illustration;
a coordinate system;
a lookup table;
a calculator;
a memory device;
a model of cyclic relations;
or some combination of these.

The correct question is not only what the circles depict.

It is what operations the reader could perform with them.

Movable Parts Compress Many States Into One Page

Suppose a manuscript needs to represent the relationship between a date and the positions of celestial bodies.

One option is to draw hundreds of separate diagrams.

A volvelle takes another route.

It stores several variables in rotating layers.

The user selects one state by aligning them.

This is physical data compression.

One page represents a family of possible configurations.

This matters for the Voynich because repeated rings and radial labels may likewise encode state spaces rather than pictures of one object.

The Hand Is Part of the Reading Process

The Getty exhibited this manuscript in Touching the Past: The Hand and the Medieval Book precisely because interaction matters.

The reader does not merely look.

The reader manipulates.

That means manuscript meaning can depend on a sequence of physical actions.

Open.

Rotate.

Align.

Read.

Compare.

This gives us a useful concept for the Voynich foldouts and radial diagrams:

the manuscript may have an interaction grammar as well as a visual grammar.

A Missing Movable Part Leaves Different Evidence From an Ordinary Missing Leaf

This creates a specific archaeological test.

If a Voynich circular page once held a movable disc, pointer or overlay, physical traces might remain.

central puncture or pivot hole;
wear around the pivot;
impressions or abrasions from rotation;
discolouration beneath a former overlay;
cut circular components or surviving attachment material;
labels positioned for alignment rather than ordinary reading.

Without such evidence, “lost volvelle” should remain a low-confidence possibility.

The comparator gives us a falsifiable expectation rather than a free imaginative device.

Astronomy and Medicine Share the Same Miscellany

The Getty manuscript is not purely astronomical.

Its catalogue title itself identifies an astronomical and medical miscellany.

Among its contents are constellation tables and medical prognostic material.

This is another deep negative control for Padua.

Medicine and astronomy interacting in one technical book is not uniquely Paduan.

The architecture appears in late-fourteenth-century England too.

Therefore the Padua hypothesis must rely on more specific regional evidence than the mere coexistence of those domains.

Constellations Can Be Operational Data

The manuscript includes Toledan constellation tables.

A constellation image can therefore be more than celestial decoration.

It can belong to a larger system of coordinates, calculation and prediction.

This is relevant to the Voynich stars and zodiac-like pages.

Repeated stars may represent:

celestial objects;
positions;
indices;
entry markers;
cyclic states;
or non-astronomical decorative symbols.

Only positional behaviour can discriminate among those roles.

The Volvelle Changes the Meaning of Concentricity

Concentric rings are common enough in medieval diagrams to be weak evidence by themselves.

But a volvelle adds a new dimension.

The rings may be designed to move independently.

Relative angle becomes information.

Alignment becomes computation.

This suggests a stronger Voynich test:

Are radial labels spaced in a way that would support alignment?

Do repeated rings have compatible divisions?

Does a central point function structurally?

Can the page encode transformations by rotation?

If not, volvelle comparison should be rejected rather than stretched.

A Manuscript Can Contain Software-Like Components

The analogy should not be taken literally, but it is useful.

A static table stores data.

A volvelle stores relationships and lets the user compute a result by manipulating the device.

That is closer to an executable interface than ordinary prose.

This matters to CivDJ because it reinforces a core principle:

representation is not only how knowledge looks; representation can determine what operations become possible.

The Pre-1386 Intellectual Sources Also Matter

The Getty catalogue associates the miscellany with a network of learned authors and translators, including Robert Grosseteste, Hippocrates, Nicholas of Lynn, William Reade and William of Moerbeke.

The physical manuscript is late fourteenth century.

The knowledge layers are older and cross-cultural.

Again we see that:

manuscript date ≠ age of every information component inside the manuscript.

A Voynich diagram could likewise inherit a much older computational convention while being drawn on fifteenth-century parchment.

What Getty Ms. Ludwig XII 7 Can Legitimately Teach Voynich Research

Medieval manuscript diagrams could contain movable parts.
The user’s hand could be part of the reading and calculation process.
A single page could encode many astronomical states through rotation.
Concentricity can support computation rather than merely depict cosmology.
Interactive astronomical devices existed before the Voynich parchment window.
Astronomy and medical prognostication could coexist in an English learned miscellany.
Lost movable components should leave physical or layout evidence that can be tested.
Manuscript information architecture can be operational rather than purely illustrative.

What It Does Not Prove

that any Voynich diagram was originally a volvelle;
that central holes in Voynich pages necessarily held pivots;
that Voynich is English;
that its circular pages calculate the Sun or Moon;
that every foldout is an interactive device;
that astro-medical integration localises the Voynich to any one university;
that visual resemblance establishes shared ancestry.

The eduKate Movable-Diagram Test

Catalogue surviving medieval volvelles before and after 1400.
Record pivot type, layer count, ring divisions, labels and calculated variables.
Record physical wear produced by manipulation.
Separate fixed diagrams from genuinely movable ones.
Build a library of layout signatures associated with movement.
Inspect Voynich circular pages for the same physical signatures.
Model hypothetical rotations only when an attachment mechanism is physically plausible.
Require the hypothetical movement to improve a coherent calculation or lookup task.
Reject movement models that merely create attractive alignments after unlimited rotation.

Student Lens: A Page Can Calculate

Primary: make two paper circles, pin them together and rotate one to match months to seasons.

Lower Secondary: compare a printed conversion table with a rotating conversion wheel.

Upper Secondary: model a volvelle as a mechanical function that maps input angles to output relationships.

JC and adult readers: treat manuscript interaction as computation: material state becomes part of the information state.

Research Sources

The Final Idea

The volvelle is a small historical shock.

The manuscript is not just carrying information.

The parchment itself becomes part of the computation.

That changes the question we ask of strange medieval geometry.

When a Voynich diagram looks like a machine, we should neither declare it a machine nor dismiss the possibility. We should ask what physical interaction the surviving page could actually support—and what evidence that interaction should have left behind.