Author: Mark Sutton

Who, you might well ask, was Servius?  Few people today have heard of him.  And if you are not among the perhaps 1 in 10000 people who have, my guess is that you are already tempted to stop reading.

In which case, I better be quick in pointing out how important this ancient writer is for Plato’s dodecahedral universe.  To explain this story, we need to go back to when I first discovered the astronomical significance of the dodecahedron.

It was May 2013, and I was six months in to thinking about my first paper model.  I had already worked out that it was made of 60 equilateral triangles composed from 360 primary Platonic scalene triangles, making up 12 pentagonal pyramids, each formed of 30 parts.  It meant that there is one primary triangle for every day of the ‘ideal year’ of ancient Babylonian astronomy.  Having visited the Biblioteca Marciana in Venice some months before, I also knew of the two elevated dodecahedra embedded in the floor of St Mark’s basilica, one of which was set with apparent cosmological significance at the high point of the church…

Reflecting on all this over a Saturday afternoon, I decided to make a second model. Cutting out card, I decorated it with the 360 scalene triangles, sticking it all together on my mother-in-law’s dining table.

Turning this cardboard construction over in my hand, it suddenly occurred to me that the whole thing would make a pretty good foundation for a star map (juxtaposing Plato’s microcosmic elements with the universe, the macrocosm).  If this were a model of the universe, I wondered whether anybody had ever thought of using it to plot the constellations.

As I moved from table to sofa, I could see that the model had two kinds of ‘vertices’.  These are the junctions where the corners of the 60 equilateral triangles meet.  When including the primary scalene triangles, twenty of these vertices divided into 12 segments of 30 degrees each. 

It seemed obvious to set one of these vertices dividing into 12 as the celestial North Pole, with the point opposite (also dividing into 12) as the celestial South Pole.  My logic was simple: that this would divide the entire model into 12 sectors, one for every month or per zodiac sign.

Out came my marker-pen on the cardboard model, and I started drawing on the lines.  Yet there was a problem.  Six of my lines went all the way from the model’s North Pole to the South Pole.  But the remaining six did not meet, each needing a diagonal to join them up.  This was getting interesting. 

I pondered some more.  With the North and South Poles set, and 12 sectors around my hypothetical universe, I now needed to find the ‘celestial equator’ (an imaginary line in the sky directly above the equator on Earth), as well as the ‘ecliptic’.  This is the path of the Sun through the zodiac, going north to the Tropic of Cancer in the summer and south to the Tropic of Capricorn in the winter.

Let’s skip the equator for now, as that took more time to get it right.  What was immediately interesting, however, was that my decorated dodecahedron had a skew line going round the edges of the primary triangles that matched very closely to the ecliptic.  Using a blue marker pen, it was a matter of moments to highlight this circle (see photo above). Another line also matched well to the Milky Way, which I shaded with dots.

And then came inspiration in a flash.  Those little diagonals meant that six of my zodiac sectors were wide and six were narrow.  Digging deep in my mind, I recalled that some zodiac constellations are longer than others, and I wondered if my cardboard model could explain it.

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A few days later, I was back home and able to check.  I found myself measuring the constellations on the inside cover of an old star book of Patrick Moore.  And the answer was clear:  Yes, there was a relationship here.  The model could explain the variation in size of the zodiac constellations.

What followed was a decade of further exploration of the dodecahedral model.  I first had to find out how to map it properly, and how to plot the stars.  I then progressed to tuning the model for different dates, as well as comparing features with ancient records.  It has been a voyage of discovery ever since.

And all that brings us back to Servius.  Because one thing was immediately obvious:  that my model naturally divided the 12 zodiac signs into sectors of 20 and 40 degrees around the model equator, rather than the usual signs of 30 degrees.  It was a fundamental feature resulting from the partial symmetry of the dodecahedron, when dividing it into 12 sectors around the poles.

Having spotted this most odd feature, I spent plenty of time looking for evidence that some ancient writer had recorded it.  I found all sorts of other evidence, but for the 20 and 40 degree sectors, none whatsoever.  To use the technical term, this feature was not ‘attested’ in the surviving records.

I even explored ancient calendars, searching for unusual records with 20 and 40 day months…  Here I instead found evidence of years with 10 months, giving other support for the model, but no evidence of this 20 or 40 day structure.

Until, that is, I found Servius.

Servius, it turns out, wrote a commentary on Virgil’s poem the Georgics (‘On Agricultural Things’ from the Greek word georgika).  I had never read Virgil’s poem, let alone heard of Servius.  Even the identity of Servius was uncertain, living around 400 AD, with his work later extended by an unknown editor.

I was led to this most obscure of books by wanting to check out an astronomical fragment, which Servius had quoted.  That concerns another chain linking Varro, Heraclides of Pontus and a shadowy figure called Empedotimus… Having found such excellent astronomical lore, I needed to read the rest of the book to see if there was more.

And, in this case, there was. For Servius kindly offers the following comment on the previous page to the Empedotimus fragment:

The Egyptians maintain that there are twelve signs, but the Chaldeans eleven: for Scorpio and Libra receive one sign, that is to say the claws of Scorpio make Libra.  The same Chaldeans are unwilling to have equal parts in all signs, but for its property one (aliud) sign has 20, another (aliud) 40, whereas the Egyptians want the parts to be 30 in all.

Aegyptii duodecim esse adserunt signa, Chaldaei vero undecim:  nam scorpium et libram faciunt.  iidem Chaldaei nolunt aequales esse partes in omnibus signis, sed pro qualitate sui aliud signum XX, aliud XL habere, cum Aegyptii tricenas esse partes in omnibus velint.

Servius, Commentary on Virgil’s Georgics I.33 (ed. Georgius Thilo, 1887, p. 140) (trans. Mark Sutton).

Here, after a decade of searching, were finally attested the sectors consisting of 20 and 40 degrees (partes) that I had found on the elevated dodecahedron. And not only that, but Sergius’ comment also gave further evidence for what already seemed to be clear: that the idea of the universe as a dodecahedron originated in Chaldea – ancient Babylonia in Mesopotamia.

At this point a critic might say:  this is not evidence of the dodecahedron, but simply of 20 and 40 degree zodiac signs.  Fair enough.  But let us challenge the critic in return, and ask for any other good reason why the Chaldeans should have done such a strange thing.  Remember, the dodecahedral model showed the 20 and 40 degree sectors.  I predicted that there should be such supporting evidence somewhere, and finally, after almost a decade, the expected evidence was found (See Supplementary Material: Criterion 5).

So, was I surprised by Servius?  Certainly not.  But I was surprised that it had taken me ten years to find him!

Mark Sutton

22 April 2023.