Book Review: "The Mysterious Spheres on Greek and Roman Ancient Coins"

[helvetica]

"The Mysterious Spheres on Greek and Roman Ancient Coins", by Raymond V. Sidrys. Archaeopress Publishing. ISBN 978-1-78969-720-2 (or ..-791-9 as ebook)

   From Sun-disks in images of the ancient Babylon culture through Greek coins to late Roman imperial coins, Raymond Sidrys has done an incredible amount of research to produce what is in fact a written and well illustrated database of coins with what one generally accepts as "globes" - (the word I shall use in the following lines).
   The number of ancient coins showing a globe in one form or another, being held, sat on, presented, supporting a rudder, supporting Victory or Nike, surrounded by wreaths, as a symbol on its own, or as decoration etc. is quite astounding. The author progresses through ancient times not only showing examples of coins, but also of ancient art and statues illustrating the well-written text.
   I found the chapter about the Beata Tranquillitas types (type: globe on altar with three stars above) of particular interest. The author reproduces a page from the work of Alten and Zschucke which shows no less than 97 different designs of globes on Beata Tranquillitas coins.
   Also of great interest are graphs showing the chronological trends of popular reverses with globes, e.g. Victory on globe, emperor holding globe, Roma seated holding globe etc.
   To describe everything in the book would need several pages here. Suffice to say the 273 page work, with its extensively illustrated pages, lists and descriptions of coin types, bibliography and index, is a delightfully informative and interesting work.

[JamesC11]

Hello helvetica! Thanks for your continuing contributions to the study of ancient coins.  Could you tell us whether the author has an hypothesis or thesis regarding the uses of these global figures?  Does he merely feel threatened by spheres (possible Freudian implications here) or does he see them as an art form, design for door stops; or is he preparing us to endure an attack on the exergual line?  Jim, Perpetual Non-Poster

[helvetica]

hahaha... not threatened.
They appear to be various forms of celestial spheres, e.g. the sun. He discusses in the introduction the history of the various forms of sphere from back in Babylonian times to the present day (e.g. the "orb" which kings and queens of England hold at their coronations) and whether they were meant to depict the earthly globe or the universe..

[Justin W]

This seems like an interesting book. I always interpreted the globe on romans coins as being earth or the world. I do know there was mysticism about the universe so that could be the earlier Greek interpretations, maybe the globe represents some view of celestial interpretations of different sights that can be seen from earth such as the sun. I’m mainly wondering why the globe which represents the world was round in Roman times. So my question is did romans think the world is round or was this just a presentable way they represented in on coins. Also I will definitely grab a copy of this book and read it when I have the time, this topic is fascinating.


Best Regards,
Justin

[Joe Sermarini]

Celestial Sphere: In astronomy and navigation, the celestial sphere is an abstract sphere that has an arbitrarily large radius and is concentric to Earth. All objects in the sky can be conceived as being projected upon the inner surface of the celestial sphere, which may be centered on Earth or the observer. - Wikipedia

[JBF]

The Earth was recognized as a sphere early on (pre-Aristotle), from the Earth's shadow on the moon from an eclipse.

Also of course, the sphere was recognized as the most perfect three dimensional shape (the circle, the most perfect two dimensional).

[JamesC11]

With the hope of not imposing boredom on this topic--I'm not convinced that the Pre-Socratics can have known (except as hypothesis) that the Earth was spheroid in shape.  My own shadow certainly doesn't suggest my personal rotundity; the shadow of Earth cast on the moon is circular, not globular, to my eye.  But by the time of Ptolemy (about 150 C.E.) Greek navigators were accustomed to sail directly across the Mare Erythraeum (Indian Ocean) to the Indian subcontinent using the monsoon season currents.  On the open ocean the curvature is apparent to the naked eye as I'm sure Joe and others can confirm (sorry to drag the Navy in again).

[JBF]

Thales reportedly noticed the curvature of the horizon, and that boats disappeared over it.
I don't see what the difficulty is for you.  Maybe you are overthinking it???

maybe the Pythagoreans just took a short cut and declared it a sphere.  But, I think they
would have known from other things.

[SC]

I don't know anything about the shadow-on-the-moon theory amongst the ancients. 

But you should look up Eratosthenes.  He died in 194 BC and had estimated the Earth's circumference.  We don't know exactly how accurate he was as we don't know exactly what his stadia convert to in terms of modern km.  But depending on the measurement he was only off by anywhere from 0.5% to 17% which is extremely accurate for a guy working over 2200 years ago.

His work involved shadows but not of the Earth on the moon.  He assumed, correctly, that the sun was very far away and therefore all of the sun's rays could be treated as parallel lines when they reached the Earth.  So he and his assistants measured the length of the shadows of identical-length rods, at exactly the same time (noon on the solstice, one of the few times that could be easily co-ordinated in the ancient world), in two Egyptian cities some 800 km apart.  The distance and difference in angles of the shadows allowed for the geometrical calculation of circumference.

From what I have read of this, it appears very clear that Eratothenes was neither the first to think the world was round not the first to estimate its size, only the first to find a viable way to measure and calculate.  In other words it was well known that the earth was round by at least the mid-third century BC, at least among the scholars of Alexandria.

SC

[JamesC11]

Consider me squashed (like the terrestrial sphere).  My real interest was in the significance the author, reviewed by helvetica, attached to use of the globe on coinage.  I will avoid overthinking by stealing a phrase from film: "Let's hope that there's intelligent life somewhere out in space / because there's b----r all down here on Earth."   Jim, Once and Future Non-Poster

[Robert_Brenchley]

Eratosthenes put so much effort into measuring the diameter that I can't believe he didn't know the earth was round before he started.