Claudius Ptolemy was a scientist and polymath who worked in Egypt around the middle of the 2nd century CE. He is most well-known for his influential works on astronomy and astrology, although he also wrote on subjects such as optics, geography and harmonics as well.

Dating

Ptolemy is primarily known for having written the single most authoritative text on astronomy in antiquity, called the Mathematical Treatise (μαθηματικἠ σύνταξις), or simply Syntaxis, which later came to be known as the Almagest in the Medieval period. Records of astronomical observations that Ptolemy made in Alexandria dating from 127–141 CE are contained in the work, indicating that the Almagest was composed sometime after 141 CE (Toomer, pg. 186).

Recent scholarship has pushed the date of the composition of the Almagest back further due to an astronomical inscription that has been recognized as being written by Ptolemy in the year 146 or 147 CE (Hamilton, The Canobic Inscription). The so-called “Canobic Inscription” is thought to represent an earlier stage in Ptolemy’s thinking, prior to the publication of the Almagest, which would indicate that he didn’t complete the Almagest until sometime after the year 150 CE.

Since Ptolemy mentions the Almagest in the introduction to his astrological work, the Tetrabiblos, this implies that the Tetrabiblos was finished later, perhaps sometime in the 150’s or 160’s. This makes Ptolemy a slightly older contemporary of the astrologer Vettius Valens.

The Tetrabiblos or Apotelesmatika and its Legacy

Ptolemy’s astrological work was apparently originally known as the Apotelesmatika, which means something like “Astrological Outcomes,” “Effects,” or “Prognostics,” although it later became known more widely as the Tetrabiblos (“Four Books”).

The later Hellenistic astrologers of the 3rd through the 7th centuries seem to have held Ptolemy in high regard. Anonymous of 379 calls him “the divine Ptolemy” (CCAG 5, 1, pg. 204: 9), and Hephaistio of Thebes refers to him as “the truth-loving Ptolemy” (ὁ φιλαλθης Πτολεμαῖος). Ptolemy’s Tetrabiblos was the only Hellenistic astrological text that was continuously transmitted and translated over the centuries since it was originally published. As a result of this, he was often thought of as the most important and influential astrologer of antiquity.

However, despite the important influence that Ptolemy had on the later traditions, his Tetrabiblos does not appear to be fully representative of the mainstream Hellenistic astrological tradition. Ptolemy’s program was to reformulate astrology as a natural science, largely along Aristotelian or Peripatetic lines, and thus make it more legitimate. One of the ways that he did this was by re-conceptualizing the mechanism behind astrology as working through some sort of celestial influence from the stars and planets. This was in contrast with earlier views which held that celestial objects were capable of giving signs of future events without necessarily being causes.

Campion argues that it was Ptolemy’s causal or naturalistic rationale for astrology that allowed it to survive into the Middle Ages and the Renaissance as a respected science (Campion, The Dawn of Astrology, pg. 208ff). Geoffrey Cornelius makes a similar argument about the importance of Ptolemy’s astrological work in affecting the survival of astrology through to modern times, although he argues that this came at the cost of obscuring the earlier theoretical foundations of astrology as rooted in divination (Cornelius, The Moment of Astrology). Holden emphasizes the technical rather than the philosophical departures that Ptolemy made from the rest of the astrological tradition, calling the Tetrabiblos an “abridged” and “deviant” version of Hellenistic astrology (Holden, A History of Horoscopic Astrology, pg. 44). To a certain extent this represents a strong reactionary movement against Ptolemy that arose in the 1980s and ’90s, partially as a result of the recovery of other Hellenistic astrological sources, and the subsequent realization that Ptolemy’s work was not necessarily representative of the mainstream of the Greco-Roman  tradition of astrology.

Ptolemy’s work is still useful and informative though, as he did not completely deviate from every part of the tradition. However, it is important to realize that he may not necessarily be the most representative example of what a typical astrologer looked like in the 2nd century CE. Rather, astrologers such as Dorotheus of Sidon and Vettius Valens appear to be much more useful examples.

Critical Editions

The first modern critical edition of the Tetrabiblos was compiled by Franz Boll, who died prematurely before he could see the project to completion, although his student Emilie Boer was eventually able to bring the text to publication in 1940:

  • Claudii Ptolemaei opera quae exstant omnia, Vol. III, 1: ΑΠΟΤΕΛΕΣΜΑΤΙΚΑ, ed. F. Boll and Æ. Boer, Teubner, Leipzig, 1940.

The same year that saw the publication of the Boll/Boer edition of the Tetrabiblos also saw the publication of Frank Egleston Robbins’ combined Greek edition and English translation of the Tetrabiblos as part of the Loeb Classical Library series. Robbins lamented in the introduction to his translation that the Boll/Boer edition had not yet been released, and thus his translation was not able to benefit from the results of their work (pg. xiv). He was forced to compile his own edition based on a collection of photographs of manuscripts that he was able to obtain.

  • Ptolemy, Tetrabiblos, ed. and trans. F. E. Robbins, Harvard University Press, Cambridge, MA, 1940 (repr. 2001).

The standard critical edition of the Tetrabiblos today is an updated version of the Boll/Boer edition that was published by Wolfgang Hübner in 1998:

  • Claudii Ptolemaei opera quae exstant omnia, vol. III, 1: ΑΠΟΤΕΛΕΣΜΑΤΙΚΑ, post F. Boll et Æ. Boer secundis curis, ed. Wolfgang Hübner, Teubner, Stuttgart & Leipzig, 1998.

Translations of the Tetrabiblos

The standard English translation of the Tetrabiblos is Robbin’s edition, although this must be used with care since, as mentioned earlier, Robbins was forced to compile his own edition of the Greek text, and he was not able to base his translation off of the more authoritative Boll/Boer edition:

  • Ptolemy, Tetrabiblos, ed. and trans. F. E. Robbins, Harvard University Press, Cambridge, MA, 1940 (repr. 2001). [Online version]  [Amazon page]

In the mid-1990’s Robert Schmidt published a set of preliminary translations of books 1, 3 and 4 of the Tetrabiblos under auspices of Project Hindsight. These translations were based off of the Boll/Boer edition:

  • Claudius Ptolemy, Tetrabiblos, Book I, trans. Robert Schmidt, ed. Robert Hand, The Golden Hind Press, Berkeley Springs, WV, 1994.
  • Claudius Ptolemy, Tetrabiblos, Book III, trans. Robert Schmidt, ed. Robert Hand, The Golden Hind Press, Berkeley Springs, WV, 1996.
  • Claudius Ptolemy, Tetrabiblos, Book IV, trans. Robert H. Schmidt, The Golden Hind Press, Cumberland, MD, 1998.

Translations of the Proclus Paraphrase

Aside from the two modern translations of Ptolemy’s Tetrabiblos mentioned above, there are also a few earlier English translations of the so-called “Proclus paraphrase” of the Tetrabiblos which were published in the 18th and 19th centuries. The Paraphrase is an abridged version of the Tetrabiblos that only survives in a single manuscript, although this one manuscript happens to be older than any of the manuscripts which contain the complete Tetrabiblos, and thus it is of some value in checking variations in the manuscript transmission.

The first English translation of the Paraphrase into English was published by John Whalley in 1701. Holden notes that this translation was actually from a Latin version of the Paraphrase rather than directly from the Greek itself (Holden, A History, pg. 181):

  • Ptolemy’s Quadripartite, or Four Books concerning the Influences of the Stars, trans. John Whalley, London, 1701.

The second English translation of the Paraphrase was published by James Wilson in 1820, this time directly from the Greek text:

  • Tetrabiblos, or Quadripartite of Ptolemy, Being Four Books, Relative to the Starry Influences, trans. James Wilson, William Hughes, London, 1820. [Available on Google Books]

The third English translation of the Paraphrase was published by J. M. Ashmand just two years after Wilson’s, also based on the Greek text:

  • Ptolemy’s Tetrabiblos, or Quadripartite: Being Four Books of the Influence of the Stars, trans. J. M. Ashmand, Davis and Dickson, London, 1822. [Available on Google Books]

Bibliography

Ashmand, J. M. (trans.). Ptolemy’s Tetrabiblos, or Quadripartite: Being Four Books of the Influence of the Stars. Davis and Dickson, London, 1822.

Boll, F. and Æ. Boer (eds.). Claudii Ptolemaei opera quae exstant omnia, Vol. III, 1: ΑΠΟΤΕΛΕΣΜΑΤΙΚΑ. Teubner, Leipzig, 1940.

Campion, Nicholas. The Dawn of Astrology: A Cultural History of Western Astrology, Vol. 1: The Ancient And Classical Worlds. Continuum Books, London and New York, 2008.

CCAG 5, 1 = Catalogus Codicum Astrologorum Graecorum, vol. 5, part 1, Codicum Romanorum, ed. F. Boll and F. Cumont, Lamertin, Brussels, 1904.

Cornelius, Geoffrey. The Moment of Astrology: Origins in Divination. Penguin Arkana, London, 1994 (rev. ed. Wessex Astrologer, Bournemouth, 2002).

Hamilton, N. T., N. M. Swerdlow, and G. J. Toomer. “The Canobic Inscription: Ptolemy’s Earliest Work” in From Ancient Omens to Statistical Mechanics: Essays on the Exact Sciences Presented to Asger Aaboe.  Ed. J. L. Berggren and B. R. Goldstein, University Library, Copenhagen, 1987, pgs. 55-73.

Holden, James Herschel. A History of Horoscopic Astrology. American Federation of Astrologers, Tempe, AZ, 1996.

Hübner, Wolfgang (ed.). Claudii Ptolemaei opera quae exstant omnia, vol. III, 1: ΑΠΟΤΕΛΕΣΜΑΤΙΚΑ, post F. Boll et Æ. Boer secundis curis. Teubner, Stuttgart & Leipzig, 1998.

Robbins, F. E. (ed. and trans.). Ptolemy, Tetrabiblos. Harvard University Press, Cambridge, MA, 1940 (repr. 2001).

Schmidt, Robert (trans.) and Robert Hand (ed.). Claudius Ptolemy, Tetrabiblos, Book I. The Golden Hind Press, Berkeley Springs, WV, 1994.

Schmidt, Robert (trans.) and Robert Hand (ed.). Claudius Ptolemy, Tetrabiblos, Book III. The Golden Hind Press, Berkeley Springs, WV, 1996.

Schmidt, Robert (trans.). Claudius Ptolemy, Tetrabiblos, Book IV. The Golden Hind Press, Cumberland, MD, 1998.

Toomer, G.J. “Ptolemy”, in The Dictionary of Scientific Biography, vol. 11, ed. Charles Coulston Gillispie, Charles Scribner’s Sons, New York, NY, 1970, pgs. 186-206.

Whalley, John (trans.). Ptolemy’s Quadripartite, or Four Books concerning the Influences of the Stars. London, 1701.

Wilson, James (trans.). Tetrabiblos, or Quadripartite of Ptolemy, Being Four Books, Relative to the Starry Influences. William Hughes, London, 1820.

Article Information

  • Author: Chris Brennan
  • Originally published: March 5, 2012 |   Last updated: March 24, 2012
  • Article notes: The article is currently incomplete, and is primarily acting as a placeholder until I have time to add the other sections.
  • Cite this article: Chris Brennan, “Claudius Ptolemy,” The Hellenistic Astrology Website, March 24, 2012, https://www.hellenisticastrology.com/astrologers/claudius-ptolemy/