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An Astronomical Diary mentioning Gaugamela

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Bust of Alexander the Great, from Delos, now in the Louvre, Paris (France). Photo Marco Prins.
Bust of Alexander the Great, from Delos, now in the Louvre.
Its official title "Astronomical Diary concerning month VI and VII of the fifth year of Artašata who is called Darius" may not sound very exciting, but this is one of the most important cuneiform sources for the eastern campaign of the Macedonian king Alexander the Great. Not only does this Astronomical Diary describe the omens before the battle of Gaugamela and the fight itself (on 1 October 331), but it also tells how the "king of Asia" entered Babylon.

The cuneiform tablets (BM 36761 + BM 36390) are in the British Museum. On this website, a new reading is proposed by Bert van der Spek of the Free University of Amsterdam (Netherlands) and Irving Finkel of the British Museum. Please notice that this is a preliminary version. This web publication is therefore intended to invite suggestions for better readings, comments and interpretations (go here to contact Van der Spek).

Babylonian Chronicles
Earlier editions
Commentary (obv.)
Commentary (rev.)
Reader's edition


The diary refers to the battle of Gaugamela and the entry of Alexander the Great into Babylon. Darius III Codomannus is referred to as "the king", Alexander as "the king of the world". In the beginning of this tablet the astral phenomena discussed above are recorded.

For a general discussion, see: Bernard 1990, Kuhrt 1990 and Van der Spek 2003.

Names of stars: According to a system proposed by Johannes Bayer in 1603, the brightest star in a constellation is called alpha, the second-brightest is called beta, et cetera. However, many stars already had proper names that are still popular: e.g., Alpha and Beta Gemini are called Castor and Pollux. In the scientific edition of the AD, the Bayer system has been used.


32 minutes. The Babylonian has 8 (UŠ) = 8 degrees. Hunger comments: “time intervals shorter than a day are measured in the diaries by the unit UŠ, which corresponds to 4 of our minutes. An appropriate translation for UŠ is “time degree” because the celestial sphere moves 1 in right ascension in the time of 1 UŠ. 1/60 of one UŠ is called 1 NINDA.” (AD I, p. 16)

20 September 331 BCE: Pisces, the eclipsed moon, and the planet Saturn (Starry Night).
20 September 331 BCE: Pisces, the eclipsed moon, and the planet Saturn (Starry Night)

Lunar eclipse. The lunar eclipse took place on 20 September 331 BC one hour and 10 minutes after sunset, while Saturn was present and Jupiter had set shortly before the eclipse was complete. A lunar eclipse while Jupiter was invisible was considered a bad omen for the reigning king. The presence of Saturn was also a bad sign.This will have added to the panic in the camp of Darius III. The eclipse was also recorded in the classical sources: Arrian of Nicomedia, Anabasis, 3.7.6:
There was an almost total eclipse of the moon, and Alexander sacrificed to the moon, Sun and Earth, who are all said to cause an eclipse. [Alexander's diviner] Aristander thought that the eclipse was favourable to the Macedonians and Alexander, that the battle would take place that month, and that the sacrifices portended victory for Alexander.
This procedure reminds us of an old Mesopotamian divinatory practice: the eclipse was merely the announcement of a divine message, the contents of which could be discovered by extispicy. Cf. Van der Spek 2003: 289-296.

3’, 5’ and 6’
broken. The text has he-pi written in a kind of cuneiform superscript. It means that this tablet is a copy of an older tablet, which was damaged. Copyists duly recorded this.

DUL must represent a verb related to rain. It is unknown what it is. Cf. Hunger, AD I, p. 30.

Winds. The direction of the wind was important for the astrological interpretation of the heavenly signs.

7 1/3. The text has 2 2/3 KŠ = 2 2/3 cubit. Hunger comments: “The distance between moon and star is expressed in “cubits” (KŠ, Akkadian ammatu) and “fingers” (SI or U, Akk. ubnu), the “finger” being 1/24th of a cubit. In the Neo-Babylonian period, 1 cubit corresponds to 2” (AD I, p. 22). The cubit is also a measure of length: 50 cm. See the article on Weights & measures
Alpha Arietis = the brightest star of the constellation Aries (Ram).

A stroke of lightning. The text has IZI ŠUB, Akk. miqitti išti,  "fall of fire". The normal sign for "lightning" is GR, Akk. birqu, derived from the verb barqu, "to flash". The miqitti išti is lightning that strikes the earth or a building. It is considered an evil omen. Cf. CAD M II, p. 102, s.v. miqittu 5; CAD I/J, p. 228, s.v. ištu 1 a 1’.

Equinox. The autumnal equinox indeed took place on 28 September 331 according to the Julian calendar.

Alpha Leonis, the brightest star of Leo, also called LUGAL = “king”, in Latin Regulus, “petty king”.

Solar eclipse. Babylonian astronomers could compute the days on which solar and lunar eclipses could take place. Solar eclipses are only visible on small parts of the earth. As a matter of fact a solar eclipse did take place on 6 October 331 BC, but it could be watched in Greenland and North America, not in Babylonia.

Exchange value. The text has KI.LAM, Akk. mahru. Hunger translates “equivalent”. The astronomers recorded the value at the shekel at the end of each month, i.e. what could be bought for one shekel (=8.33 gr.) of silver of 6 commodities: barley, dates, cuscuta or mustard, cress, sesame and wool. The astronomical diaries contain a exceptionally detailed database for commodity prices in Babylonia. The data are collected on the website of the International Institute for Social History in Amsterdam (more...). Prices had been high in the late Achaemenid period, but in the decades preceding the invasion Alexander they had fallen.180 litres of dates for 1 shekel of silver is a fair price. The prices however would rise sharply after Alexander’s invasion and even more after his death when the Wars of the Successors broke out.

Panic occurred because of the advance of the army of Alexander (Curtius Rufus, History of Alexander of Macedonia, 4.12.14). This army must have been mentioned in the break. Macedonians are often referred to as Hanaeans, a western nomadic tribe and kingdom on the middle Euphrates in the Middle Babylonian period. This belongs to the archaizing tendency of diaries and chronicles in rendering geographic names. This makes them more useful for comparison with omens. The same holds true for Gutians (people living to the east of the Tigris) in line 18’.

The battle of Gaugamela. Design Jona Lendering.

15’, rev.11’
The king of the world. The text has LUGAL Š, Akk. šar kiššati. Technically it is also possible to read: LUGAL-š, “its king” i.e. king of the land of Hani (Macedonia). So in the Nab-Nasir to Šamaš-šuma-ukin Chronicle (ABC 1, IV 27) where mention is made of the city of Memphis and “its king”. In view of the context, esp. in rev. 11’, and in view of the fact that the expression LUGAL Š occurs in many omens, I opt for the translation “king of the world” (as Hunger did). It must be the translation of Alexander's  title "king of Asia", because "Asia" was no recognizable concept for a Babylonian scientist (cf. Van de Spek 2003, 299).

In the morning. Plutarch (Alexander, 32.2) maintains that Alexander overslept on the day of the battle. The story is probably a myth.

This word order, object – subject – verb, is typical for omens. This particular omen (“the king, his troops will abandon him”) is given in the Babylonian astrological calendar for lunar eclipses in months III, VIII and X (Labat 1965, 72:3; 73:7 and 10).

Note that the text says that Darius was deserted by his troops instead of the other way around, as is maintained by Arrian (Anabasis 3.13.3), but Curtius Rufus (4.15.28-33) and Diodorus of Sicily (Library of World History, 17.60.3) present the same picture as the diary. Cf. the chapter on Gaugamela in Lendering 2004 (translation online).

The land of the Gutians. The diaries often use archaic geographical names. The land of the Gutians stands for the mountainous regions east of the Tigris. Darius fled in the direction of Ecbatana. Alexander marched to Babylon.

The length of the Babylonian month is 29 or 30 days. Hermann Hunger gives the following explanation for the terminology used here. “The diaries are arranged in sections each of which deals with a single month. Each section begins with the name of the month; after the name, a “1” indicates that the preceding month had 30 days; a “30” that it had only 29. The idea behind this terminology seems to be that a “regular” month ought to have 30 days, in which the next month begins with a “1st” day; if a month has only 29 days, its successor begins, so to speak, already on the “30th” day which would have been theoretically possible for the preceding month.” (AD I, p. 38).

to part four (commentary reverse)

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