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In: Atti del XVI Convegno della Societŕ Italiana di Archeoastronomia “Quis dubitet hominem coniungere caelo?”, a cura di E. Antonello, ed. La Cittŕ del Sole, Napoli, pp. 69-77, ISBN 978-88-8292-504-8.




Mario Codebň, Athanasios Fourlis





Commonly, the adjective πκιρρος, that Ptolemy used for only six, different stars in his Almagest and for only three stars in his Tetrabiblos, is translated “reddish”. Because these stars have very different colours at the present, modern astronomers were always obliged to try to explain why Sirius was described as “reddish” instead of white (as it really is) by Ptolemy. Several hypotheses were advanced. We propose here:

1) a “strong” hypothesis that the adjective πκιρρος means “yellowish”;

2) a “weak” hypothesis that πκιρρος means “iridescent”;

3) the witness written in the Avestā, the holy book of the Zoroastrian religion, that the colour of Sirius before Ptolemy was white.





In the Stars’ Catalogue of his Μαθηματική Σνταξις, commonly known as The Almagest, Ptolemy describes 1022 stars from the first to the sixth magnitude, but only for six of them he uses an adjective – πκιρρος – that always had been translated as “reddish”. The six stars are:

Aldebaran (spectral class K5)

Antares (spectral class M1)

Betelgeuse (spectral class M2)

Arcturus (spectral class K1)

Pollux (spectral class K0)

Sirius (spectral class A1).

For the human eyes two of these stars – Antares and Betelgeuse – seems to be really red; two others – Aldebaran and Arcturus – seems to be orange; one – Pollux – seems to be yellow and the last one – Sirius – seems to be white.

In his book Τν πρός Σύρον ποτελεσματικν τέσσαρα βιβλία, commonly known as The Tetrabiblos (Feraboli 19892, pp. 42, 44; 48), Ptolemy uses the same adjective πκιρρος only for three stars: Aldebaran (names here λαμπαύρας = bright), Antares and Arcturus. Here he does not use any adjective for Betelgeuse, Pollux and Sirius.

This opens three questions:

1) What is the exact meaning of the adjective πκιρρος?

2) Why Ptolemy only used an adjective for six stars out of 1022 in the “Stars’ Catalogue” of his Almagest (Heiberg 1903; Toomer 1998)?

3) Why did he used the same adjective for so many, different coloured, stars?



2.Schiaparelli’s hypotheses


The common translation of πκιρρος into reddish obliged astronomers to explain how it is possible that a reddish star changed its colour into white in a span time less than one millennium, because the Muslim astronomer Al Sufi describes Sirius as white star in the 10th century AD (Ferreri 2015, p. 40).

Because Sirius is a double star, a modern hypothesis tries to explain the change of colour as the transformation of Sirius B, previously giant and red, into the present white dwarf star (Ferreri 2015, pp. 40 – 42).

But this hypothesis is not very convincing.

The Italian astronomer Giovanni Virginio Schiaparelli wrote, respectively in 1896 and in 1897, the two important reports Rubra Canicula. Considerazioni sulla mutazione di colore che si dice avvenuta in Sirio and Rubra Canicula. Nuove considerazioni sulla mutazione di colore che si dice avvenuta in Sirio (De Meis, Gnoli, Panaino 1998, pp. 179 – 234) supposing that the change of colour was only a translation mistake since the Roman Age. He supposed, with convincing arguments, that the Latin translation “Rubra Canicula” – i.e. the “little female reddish dog” – is related not to Sirius but to the red star Procyon in Canis Minor constellation, that rises some days before Canis Major. Indeed Schiaparelli describes the ancient Greek myth of Icarius, of his daughter Erigones and of their little female dog Maira who were all changed in heavenly constellations (respectively: Bootes, Virgo and Procyon or Canis Minor) by the Olympians Gods. He describes also an ancient Latin sacrifice – the Robigalia – on occasion in which, every 25th April, Romans sacrificed a little red female dog to Robigo, the goddes of the rust. Schiaparelli infers that Rubra Canicula, Maira, the Robigalia and Procyon had the same meaning and that Romans mistook the red star Procyon for Sirius.



3.Etymological discussion

We think that this confusion between Procyon Rubra Canicula and Sirius πκιρρος led wrongly to translate this adjective as reddish. But πκιρρος does not mean reddish!



3.1 The meaning of κιρρς


According to the dictionaries Gemoll 19367 and Rocci 1948, these are the meanings for πκιρρος, κιρρς and their compounds:

a) κίρρος or κιρρός = pale, yellow;

b) πόκιρρος = yellowish;

c) κιρράς = yellow;

d) κιρροειδής = yellowish; pale;

e) κιρροκοιλάδια = figs with yellow pulp;

f) κιρρώδης = yellowish.

The adjective κιρρός gives in modern languages the medical word “cirrhosis”, because the liver becomes yellow owing to the adipose (or fat) infiltration;: κίρρωσις = κιρρός (yellowish) and -ωσις (condition).

Basically, the ancient authors used these adjectives meaning yellow or white. For instance, Hippocrates wrote πόκιρρος ονος, means “white wine”.

Therefore, πκιρρος does not mean a dark colour, as reddish, but, rather, a very clear colour as yellowish or whitish, that is the current colour of Sirius. Please, note that, in ancient Greek, σείριος means “hot”, “burning”. Eratosthenes, in his work Καταστερισμοί (Westermann, 1843), wrote “Seirios on the head [or tongue]. This star is large and very bright (λαμπρν[1]) and the stars similar to it are named Seirioi by astronomers because of the movement of the flame”. The movement of the flame is important!

So the very true question is: why Ptolemy used an adjective that means “yellowish or whitish”, not “reddish”, for red stars as Antares, Betelgeuse and for orange stars as Aldebaran and Arcturus[2]?

In ancient Greek grammar πόκιρρος is a compound word (πό+κιρρς) but the word πό is a preposition (Latin: ipo-; Engish hypo- = sub, under, down, below), that, placed before the adjectives, decrease their characteristics (downgrading the original word): for example: υποαλλεργικό (=hypoallergenic), υποθερμία (=hypothermia).

This fact alone is enough to cancel the ''red–theory'' even if some researchers wrongly translate the adjective κιρρός as “red”, influenced by the Latin “ruber, rubra, rubrum”.



3.2 Κιρνάω, κεραννύω, κεράω, κερννυμι


Another fact is that κιρρς may have the same root of κιρνάω, κεραννύω, κεράω, κερννυμι, meaning basically “to mix”, signifying the mixing and the consequently “change” (of colour, consistency, etc.). Indeed, these verbs were used (for instance in Homer) to signify the mixing of the wine with the water. But when the dark wine is mixed with water its colour changes, becoming more clear or “pale” (i.e. κιρρς). In other words, the colour κιρρς may derive its meaning “yellow, pale” from the change of the colour of dark wine mixed with water.



3.3 The colours in the antiquity


It seems that in ancient languages did not exist the colours in the abstract as in modern ones[3], but the colours were derived from material objects having that colour (for instance: the red of the fire; the blue of the sky; etc. And the “bleaching” of the dark wine mixed with water)[4].

After Greek words were taken into Latin, the letter “K” was transliterated as a “C”. Loanwords from other alphabets with the sound /K/ were also transliterated with C. Hence, the Romance languages generally use C and have K only in later loanwords from other language groups. The Celtic languages also tended to use C instead of K, and this influence carried over into Old English. (

Let's see now some examples about the preposition πό from the book written by Pedanius Dioscorides, De Materia Medica (ΠΕΔΑΝΙΟΥ ΔΙΟΣΚΟΥΡΙΔΟΥ ΑΝΑΖΑΡΒΕΩΣ, Περ λης ατρικς) (Wellmann 1906). Now we can see how this preposition can transform (“decrease” in this case) the adjective/colour but we can now also understand the colours through the eyes of ancient people, as a comparison of ancient and modern colours in the same object:

a) Wax <κηρς> = πκιρρος = subpale [Vol II, 83][5]

b) Sea daffodil bulb (Pancratium Maritimum) <παγκράτιον> = πόπυρρος (reddish, sub+color of the fire, pyrros)[Vol II, 172]

c) Honey <μέλι> = πόξανθον (sub+color of blond hair, blond = xanthos) [Vol II, 82]

d) Anemone (for the white species) <νεμώνη> = πόλευκα (sub+white, whitish, white = lefkos) [Vol II, 176]

f) Thlaspi Arvense <θλάσπι> = πόλευκον (sub+white, whitish, white = lefkos) [Vol II, 156]

Furthermore an other example (Ulrichs, 1843):

albŏgilvus, a, um = πόλευκος, κιρρός [6] (= whitish, kirros).

Some more synonyms for πόλευκος are: ivory, pale, pallid, creamy-white, broken-white, off-white.



3.4 The root *κιρ/*κηρ and the Linear B


An additional hypothesis is that some words derived from the same root and widespread in several cultures are related. The word <kera> (κέρας), the root of which may be *κιρ/*κηρ, is already present in the Linear B until today. Its meaning is “horn”. Some derivatives words are:

 Ceratophyllum, rhinoceros, keratin, cheratina, cranium, cranio (skull), cranosn (helmet). Common-root in Linear B <ka-ra-pi>, cara (cerebrum, head).

But the same root you can actually find in the modern and ancient Greek adjective κιρρς = “pale”, that Macedonians pronounce κερρς, with an ε = e instead of an ι = i (Hoffmann, 1906). Here we have the same meaning with two different pronunciations! Moreover, the colour of the horn is generally a kind of lighter or darker “yellow”: i.e. “pale”.

The same root *κιρ/*κηρ may also appear in some words meaning baked clay, pottery, the colour of which is generally “pale”.

These examples proof again, that the original meaning of the adjective πκιρρος is not reddish but “yellowish”, “whitish”, at least “pale”.



4. Avestā’s and other witnesses


Regarding the colour of Sirius, we have a witness prior to Ptolemy that describes it as a white star: in the Avestā (Alberti 2008, pp. 320 – 329), the holy book of the Zoroastrian religion, the Yašt Tīr n. 8 is devoted to the star Tištria, that is the yazata (i.e. roughly the angel) of the star Sirius. The Yašts are thirty hymns, one for each day of the months, devoted to the “yazata”. Some of them precede the Zarathuštra’s religious reform (about 9th century BC or before). They were composed during the 1st millennium BC, i.e. before the Ptolemy’s Almagest.

Yašt Tīr n. 8, vers No. 2, sings:

<We offer up libations unto Tištrya, the bright and glorious star, that gives happy dwelling and good dwelling; the white[7], shining seen afar, and piercing; the health-bringing, loud-snorting, and high, piercing from afar with its shining, underfiled [immaculate][8] rays, and unto the waters of the wide sea, the Vanguhi of wide renown, and the species of the Bull, made by Mazda, the awful kingly Glory, and the Fravashi of the holy Spitama Zarathushtra>[9].

Moreover, some extant ancient chinese texts – from 100 B.C. to 646 A.D., i.e. about contemporary to Ptolemy – also report that the colour of Sirius was absolutely white, as Vega. (Jiang Xiao-Yuan, 1993):

1) Shiji Tianguanshu (Historical Records, Book of asterisms) written by Sim Qian in 100 B.C.

2) Hanshu Tianwenzhi (History of Hall, Astronomical Chapter) written by Ban Gu, Ban Chao and Ma Xu in 100 A.D.

3) Jinzhou Zhan (Jinzhou Book of Prognostication) written by Liu Biao in 200 A.D.

4) Hanshu Tianwenzhi zhong (History of Jin, Astronomical Chapter, Book 2 of 3), written by Li Chun-Feng in 646 A.D.

Please, note that Vega is mentioned in the Avestā too: the short Yašt 20 is fully devoted to Vanant, that is probably the star Vega (α Lyrae), named the “star of the rains”. Vanant is mentioned in the Yašt 8,12 too, with Tištrya (Sirius, that is named here “the first star”) and the stars Haptōiringa, that seem to be the stars of the Ursa Major (the Great Bear or the Plough). Here is the full verse 12 of the Yašt 8, according to

<We sacrifice unto Tishtrya; We sacrifice unto the rains of Tishtrya. We sacrifice unto the first star; we sacrifice unto the rains of the first star. I will sacrifice unto the stars Haptoiringa, to oppose the Yatus and Pairikas. We sacrifice unto Vanant, the star made by Mazda; for the well-shapen strength, for the Victory, made by Ahura, for the crushing Ascendant, for the destruction of what distresses us, for the destruction of what persecutes us. We sacrifice unto Tishtrya, whose eye – sight is sound.>.

Also Schiaparelli, in his article of 1896 (De Meis, Gnoli, Panaino 1998, pp. 205 – 209), listed and discussed the ancient authors who described Sirius as a white star or, at least, not as a reddish one: Julius Iginus; the scholiast of Aratus; Manilius; Rufus Festus; Hefestio of Thebes (in Egypt). The last of them, particularly, described four colours (big and white; gold; red; little and pale) and four qualities (big and bright; dull; little and dim; dark[10]) that Sirius could show during its heliacal rising[11], heralding the Nile’s floods. This mutability of Sirius, due to the atmospherical absorption, is in agreement with our “translation” of the adjective πκιρρος as “iridescent”.



5. Conclusions

Κιρρς does not mean reddish but yellow and therefore, πόκιρρος (or ποκιρρς) means “less than yellow”, which is the true colour of Sirius. But the question is: as this adjective does not fit on to the other four “reddish” stars Aldebaran, Antares, Betelgeuse, Arcturus, as listed by Ptolemy, why Ptolemy used the same adjective for so many different stars and only for those six, while he named 1022 stars, for which he used only the adjective λαμπρός = bright?

Because the verbs κιρνάω, κεραννύω, κεράω, κερννυμι (that may have a common root *κιρ/*κηρ) meaning “to mix”, because these verbs are used by ancient authors to express the action of the mixing of wine and water – in consequence of which the red wine change its colour and becomes more pale – we suggest the hypothesis that πόκιρρος meant in Almagest the quick change of colour of these six bright stars, i.e. their iridescence.

This is only a proposal of course, a work hypothesis without proofs, not a certainty! On the other side, our purpose in this article is not to search for the true meaning of the adjective πόκιρρος but to check if it means reddish, as commonly translated, and consequently if Sirius was once truly reddish and changed its colour in less than one millennium. We think, with adequate certainty, that we proved here that it does not mean reddish[12]. Moreover, we found the new, unpublished witness of Avestā, supported by Chinese witnesses and by the authors listed by Schiaparelli nearly contemporary of Ptolemy, which demonstrates that Sirius, at the age of Ptolemy, was already white.




Claudio Bevegni, Ancient Greek, University of Genova, Italy.

Mario Caprini, Literature, High School teacher. Italy.

Rita Caprini, Glottology, University of Genova, Italy.

Walter Ferreri, Astronomer, INAF – Osservatorio Astronomico di Torino, Italy.

Agostino Frosini, ship commander.

Maria Giannikou, Philology, School consultant of philologists, University of Ioannina, Greece.

Stelios Kaouris, Philology, Aristotle University of Thessaloniki

Konstantinos Kottis, Theology, Graduate Student , Aristotle University of Thessaloniki, Greece.

Alexandra Schmitz, Academy of Fine Arts of Florence



Alberti Arnaldo (2008) Avestā, UTET, Torino, Italy.


De Meis S., Gnoli G., Panaino A. (1998) Giovanni Schiaparelli. Scritti sulla storia dell’astronomia antica, 2nd volume, Mimesis, Milano, Italy.


Feraboli S. editor (19892) Claudio Tolomeo. Le previsioni astrologiche (Tetrabiblos), Fondazione Lorenzo Valla/A. Mondadori, Milano, Italy.


Ferreri Walter (2015) Il mistero di Sirio rossa, Nuovo Orione, n. 279, Italy.


Gemoll Guglielmo (19367) Vocabolario Greco – Italiano ad uso delle scuole, Edizioni Remo Sandron, Palermo – Milano, Italy.


Heiberg J.L. (1903) Syntaxis Mathematica, Lipsia, Germany.


Hoffmann, O. (1906) Die Makedonen, ihre Sprache und Volkstum,


Vandenhoeck & Ruprecht, Göttingen, Germany.


JIANG Xiao-Yuan (1993) The colour of Sirius as recorded in ancient Chinese texts, Chinese Astronomy and Astrophysics, 17, 2, 223-228.


Köbler, Gerhard (2007) Altgriechisches Herkunftswörterbuch (


Lewis C.T. and Short C. (1879) A Latin Dictionary, Clarendon Press, Oxford, UK.


Lewis C.T. (1891) An Elementary Latin Dictionary, New York: Harper & Brothers, USA.


Liddell-Scott-Jones (1904) Μέγα Λεξικόν τς λληνικς Γλώσσης., tr. by A. Konstantinidis (


Rocci Lorenzo (1948) Vocabolario Greco – Italiano, Societŕ Editrice Dante Alighieri, Italy.


Smith William, editor (1813-1893) A Dictionary of Greek and Roman Geography, volume 1 & 2, published: Walton and Maberly (1856-68), London, UK. (


Smith William, editor (1890) A Dictionary of Greek and Roman Antiquities, published: John Murray (1875), London, UK (;view=1up;seq=1).


Thurston Peck H., editor (1898) Harper's Dictionary of Classical Antiquities, Harper & Brothers, New York, New York, USA.


Toomer G.J. (1998) Ptolemy’s Almagest. Princeton University Press, Princeton, New Jersey, USA.


Tselentis Chris (2011) Linear B Lexicon, Athens, Greece (


Ulrichs, Heinrich Nicolaus (1843) Lexicon Latinum-Graecum scriptum et editum ab Henrico Nicolao Ulrich, (ed.) Εκ της Βασιλικής Τυπογραφίας, Athens, Greece. (


Wellmann Max (1906) Pedanii Dioscuridis, De materia medica, libri quinque, Berolini apud Weidmannos Publisher, University of Glasgow, Library (


Westermann A. (1843) Mythographoi. Scriptores poeticć historić Grćci, Braunshweig (Brunsvigae), Germany.


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[1]      λαμπρν is the adjective more often used in the catalogue of the stars in the Almagest.

[2]      For the yellow star Pollux, πκιρρος may be fitted.

[3]      Probably only the difference between brightness and darkness.

[4]      Personal communication to us by prof. Mario Caprini and prof. Rita Caprini.

[5]      The numbers between square brackets are referred to the volumes, chapters and lines of Dioscorides’s book.

[6]      Please, note that Latin adjective albus, -a, -um means “white”. This is another proof that κιρρς – and even more so πκιρρος – does not mean “reddish” but “whitish.

[7]      The underlining is made by us.

[8]      The underlining is made by us.

[9]      English version by “Avesta Zoroastrian Archives”

[10]     μγας κα λαμπρός; μέλας; μικρὸς καὶ στυγνός; σκοτεινός.

[11]     For astrologers who had to foresee the discharge of the Nile’s flood.

[12]     There are not yet enough data to state with certainty what Ptolemy wanted to signify with πκιρρος.