Nechepso and Petosiris were a pair of legendary figures whose names were attached to a highly influential set of astrological texts in antiquity.  Together they were the most widely quoted and influential authors during the Hellenistic tradition of astrology, from the 1st century BCE until approximately the 7th century CE.

The two were often treated as a pair, although sometimes one was cited independently from the other, which makes the relationship between them somewhat obscure.

The works attributed to them are generally thought to have been composed sometime around 2nd century BCE, although it may have been as late as the 1st century BCE, as the earliest reliable references to them do not appear until the early 1st century CE.

Names

Nechepso is frequently referred to as “the king” (ὁ βασιλεύς).  Vettius Valens sometimes calls him “the compiler” (ὁ συγγραφεύς).

Together Nechepso and Petosiris are sometimes referred to as “the Egyptians” or “the ancients” (οἱ παλαιοί).

Ptolemy once seems to refer to Petosiris as “the ancient one” (τὸν ἀρχαῖον) during a discussion of the length of life technique (Ptolemy, Tetrabiblos, 3, 11: 1), although this is an inference based on other authors who associate Petosiris with the technique that was used to measure the length of a native’s life.

Dating

The earliest reliable reference to Nechepso and Petosiris by an astrologer is from Thrasyllus, who died in the year 36 CE.  Only a summary of the work that contains this reference by Thrasyllus survives, but presumably it was written sometime around the early 1st century CE.  This would place the Nechepso-Petosiris text(s) as having been composed sometime in the 1st century BCE at the latest, although some scholars have speculated that it could have been written as early as the late 2nd century BCE.

Works

The title of Petosiris’ work was Astrological Matters (Ἀστρολογούμενα) according to the Suda, a 10th century Byzantine Greek dictionary and encyclopedia.

Valens mentions a work by Petosiris known as the Horoi (Ὅροι), which could mean either Boundaries or Definitions (Valens, Anthology, 2, 3: 3).  The title Boundaries might connect it with the astrological concept known as the “bounds” or “terms,” although on the other hand it would not be surprising for one of the purported founders of Hellenistic astrology to have written a work defining basic concepts.  The only thing that Valens tells us about the work in this particular chapter is that Petosiris dealt with the Lot of Fortune in a way that was similar to Nechepso.

Bibliography

Pingree, David, “Petosiris, Pseudo-,” Dictionary of Scientific Biography, vol. 10, ed. Charles C. Gillispie, Charles Scribner’s Sons, New York, NY, 1974, pgs. 547-549.

Ptolemy, Claudius, “Tetrabiblos,” ed. Wolfgang Hübner, Claudius Ptolemaeus, Opera quae exstant omnia, vol 3, 1: ΑΠΟΤΕΛΕΣΜΑΤΙΚΑ, Teubner, Stuttgart & Leipzig, 1998.

Riess, Ernestus (ed.), “Nechepsonis et Petosiridis fragmenta magica,” Philologus, supplement 6, 1891-93, pgs. 325-394. [Available online as a PDF:  Riess, Nechepsonis et Petosiridis fragmenta magica]

Rochberg, Francesca, “Petosiris,” in The Encyclopedia of Ancient Natural Scientists,  ed. Paul T. Keyser, Georgia L. Irby-Massie, Routledge, Abingdon, Oxon/New York, NY, 2008, pgs. 637-8.

Suidae Lexicon, ed. Ada Adler, Verlag Teubner, Stuttgart, 5 vol., 1928-1938.

Valens, Vettius, “Anthology,” edited in Vettii Valentis Anthologiarum Libri Novem, ed. David Pingree, Teubner, Leipzig, 1986.

Article Information

• Author: Chris Brennan
• Originally published: January 21, 2012 |   Last updated: May 10, 2012
• Article notes:  This article is currently incomplete, and it is acting as a placeholder until it can be finished.
• Cite this article: Chris Brennan, “Nechepso and Petosiris,” The Hellenistic Astrology Website, May 10, 2012, http://www.hellenisticastrology.com/astrologers/nechepso-and-petosiris/