First Section of the Ptolemaic Canon

Ancient astronomers required an accurate and uniform system of chronological markers to synchronise observations (such as solar eclipses) with their daily lives and, thereby, facilitate mathematical assessments of the movement of various celestial bodies. The markers of choice were lists of rulers and of the years they sat on the throne. This system had a long pedigree dating back to Mespotamian king lists of the second and first millennia BC.

For historians, these lists are immensely valuable as they allow for the synchronisation of data found in disparate sources, that is if they are accurate. Fortunately, Claudius Ptolemy's so-called "Canon," one of the tabular appendices to his major astronomical treatise, the μαθηματική σύνταξις (Mathematical Synthesis), better known by the westernized version of its Arabic title as the Almagest, is very accurate indeed, since it clearly ultimately derives from archival or documentary material. This is unequivocally corroborated by the evidence provided by the Babylonian chronographic texts, such as the Synchronistic King List [/ribo/kinglists/synchronistickinglist/index.html] and the other documents detailed in this section, as well as the astronomical diaries [http://www.livius.org/articles/concept/astronomical-diaries/?] and papyrological evidence from Egypt.

Claudius Ptolemy of Alexandria [https://www.livius.org/sources/content/ptolemy-of-alexandria/], or Klaudios Ptolemaios in Greek, who lived in the first and second centuries CE (ca. 85-165 CE), was not only a famous astronomer but also a mathematician and natural scientist. Deeply influential in Arabia and Europe at least until the 16th century CE, his interests ranged from music and harmonics to geography and planetary motion. A prolific scholar, most of his works have survived and shaped scientific thought well into the Renaissance; his astronomical work, for instance, was superseded only by the work of Copernicus.

The list that establishes Ptolemy's particular relevance to Babylonian scholarship was the product of continuous scientific improvement over generations. His Canon began in Babylon in the early 1st Millennium BC and did not end with Ptolemy's death: there are versions of the list from as late as the 15th century CE. The version of the Canon that he himself codified spanned the centuries from the first regnal year of Babylonian king Nabû-nāṣir [/ribo/babylon6/earlyfirstmillenniumrulers/nabunasir/index.html] (747 BC) to the reign of Roman Emperor Antoninus Pius († 161 CE). The dating system is based on the uniform Egyptian calendar traditionally used by Hellenistic astronomers, which treated each solar year as consisting of exactly 365 days with no leap year, rather than on the Julian calendar in use in Ptolemy's time. Unlike most solar or lunar calendar systems with their varying year lengths, this uniform scale allowed for the exact and easy computation of intervals. Its drawback is that it causes the year to wander and diverge from the naturally observable passage of the seasons: only after 1,460 years have passed, does it fall into step with nature again.

The king list

The list begins with rulers of the period of the Uncertain Dynasties [/ribo/babylon6/index.html] (978-626 BC) and continues beyond those of the Ptolemaic Period [http://www.livius.org/articles/dynasty/ptolemies/] (304-30 BC). The translation below (by Jamie Novotny) contains the first part of the Ptolemaic Canon, which is the section pertinent to the Babylonian corpora presented here.

Due to their intended use as astronomical reference charts, historical use of such lists must be prefaced with some words of caution.

• The lists usually pretend that kings reigned only whole years. Kings thus usually lent their name to the year of their death, based on the fiction that the next ruler would have ascended to the Babylonian throne on the first day of the new year. Furthermore, periods of transitional uncertainty and counter-kingship are ignored if they lasted for less than a year.
• The two periods marked as 'kingless' below are due to unrecognised conquerors or usurpers. The first period is marked by the short-lived usurpations by Marduk-zakir-šumi and Marduk-apla-iddina, whereas the second is due to Sennacherib's destruction of Babylon. The list picks up again with Esarhaddon's restoration of that city.
• Finally, the authenticity and reliability of Ptolemy's chronological table has been called into question on the basis that Ptolemy must have falsified his observations to preserve the integrity of his, as we now know, scientifically incorrect model of the solar system. Whether he indeed did so or not, is, however, irrelevant for the study of the Neo-Babylonian chronology, since this chronology is no longer contingent upon the observations recorded by Ptolemy.

Select Bibliography

Depuydt, L., "'More valuable than all Gold': Ptolemy's Royal Canon and Babylonian Chronology," in: Journal of Cuneiform Studies 47 (1995), pp. 97-118.

Folkerts, M. and Harmon, R., "Klaudios Ptolemaios [Ptolemaios 65]", in: DNP 10 (2001), cols. 559-570.

Grasshoff, G., The History of Ptolemy's Star Catalogue, London 1990, pp. 79-91.

Grayson, A.K., "Königslisten und Chroniken. B. Akkadisch," in: D.O. Edzard (ed.), Reallexikon der Assyriologie und Vorderasiatischen Archäologie 6/1–2, Berlin/New York: de Gruyter, 1980, p. 101 §3.8.

Neuffer, J., "'Ptolemy's Canon' Debunked?", in: Andrews University Seminary Studies (AUSS) 17:2 (1979), 39-46.

Neugebauer, O., A History of Ancient Mathematical Astronomy, Berlin 1975.

Newton, R.R., The Crime of Claudius Ptolemy, Baltimore 1977.

Wachsmuth, C., Einleitung in das Studium der Alten Geschichte, Leipzig 1895, p. 305.

Ptolemy's Canon [http://www.livius.org/cg-cm/chronology/canon.html] page on Livius.org [https://www.livius.org/articles/concept/ptolemys-canon/] (Accessed 24.11.2016).

Henry Heitmann-Gordon

Henry Heitmann-Gordon, 'First Section of the Ptolemaic Canon', The Royal Inscriptions of Assyria online (RIAo) Project, The RIAo Project, a sub-project of MOCCI, 2023 [http://oracc.museum.upenn.edu/riao/kinglists/ptolemaiccanon/]