Babylonian wisdom: Diodoros on Chaldeans’ astrology and divination (mid-first century BCE)

Citation with stable link: Philip A. Harland, 'Babylonian wisdom: Diodoros on Chaldeans’ astrology and divination (mid-first century BCE),' Ethnic Relations and Migration in the Ancient World, last modified May 11, 2024,

Ancient author: Diodoros of Sicily, Library of History 2.24; 2.29-31; 17.112; 19.55 (link).

Comments: Diodoros’ discussion of Chaldeans among Babylonians may in some ways fit under the rubric of Greek notions about “wise barbarians” as he sometimes points out Greek deficiences in relation to Chaldean strengths. But in other ways his discussion seems to hesitate from full endorsement and comes across as an ethnographic description of one segment of the population. In any case, Diodoros does make many positive evaluations of the Chaldeans as he describes their lifestyle and activities, focussing most on divination and, especially, astrology. In a separate passage, Diodoros also provides an anecdote involving a Chaldean. Diodoros does not reveal the sources for his claims. Finally, Diodoros draws on sources that claim that the Chaldeans accurately predicted the death of Alexander of Macedon at Babylon despite Greek philosophers at the time arguing to the contrary. That final story does suggest a competition in which barbarian wisdom triumphs over Greek wisdom.


[For Diodoros’ / Ktesias’ preceding discussion of the Assyrians, go to this link]

[Example of Belesys, the Chaldean priest who assisted in the fall of the Assyrian empire]

(2.24) A certain Median named Arbakes, who was conspicuous for his bravery and nobility of spirit, was the general of the contingent of Medes which was sent each year to Ninos [legendary Assyrian king]. Having made the acquaintance during this service of the general of the Babylonians, he was urged by him [the Babylonian] to overthrow the empire of the Assyrians. (2) Now this man’s name was Belesys, and he was the most distinguished of those priests whom the Babylonians call “Chaldeans.” Since as a consequence he had the fullest experience of astrology and divination, Belesys could accurately foretell the future to the people in general. Therefore, being greatly admired for this gift, he also predicted to the general of the Medes, who was his friend, that it was certainly fated for him to be king over all the territory which was then held by Sardanapallos [legendary king of Assyria]. . .


[Chaldeans and divination]

(2.29)  But it seems not inappropriate for us to speak briefly about the Chaldeans of Babylon and about their antiquity, so that we may omit nothing which is worthy of recording. (2) Now the Chaldeans, belonging as they do to the most ancient inhabitants of Babylonia, have about the same position among the divisions of communal organization as that occupied by the priests of Egypt. For being assigned to the service of the gods they spend their entire life in study, their greatest renown being in the field of astrology. But they occupy themselves largely with divination (mantikē) as well, making predictions about future events, and in some cases by purifications, in others by sacrifices, and in others by some other charms they attempt to avert evil things and facilitate good things. (3) They are also skilled in divination by the flight of birds, and they give out interpretations of both dreams and portents. They also show marked ability in making divinations from the observation of the entrails of animals, considering that in this branch they are eminently successful.


The training which they receive in all these matters is not the same as that of the Greeks who follow such practices. (4) For among the Chaldeans, the philosophy about these subjects is passed down in the family, and son takes it over from father, being relieved of all other services to the community. Since, therefore, they have their parents for teachers, they not only are taught everything without hesitation but also at the same time they listen to the precepts of their teachers with a most unwavering trust. Furthermore, since they are raised with these teachings from childhood up, they attain a great skill in them, both because of the ease with which youth is taught and because of the great amount of time which is devoted to this study.

(5) Among the Greeks, on the contrary, the student who takes up a large number of subjects without preparation turns to the higher studies only quite late. Then, after working on them to some extent, the student gives them up, because he is distracted by the necessity of earning a livelihood. But a few here and there really focus on the higher studies and continue in the pursuit of them as profit-making business, and these are always trying to make innovations in connection with the most important doctrines instead of following in the path of their predecessors. (6) The result of this is that the Chaldeans, by sticking to the same things always, keep a firm hold on every detail, while the Greeks, on the other hand, aiming at the profit to be made out of the business, keep founding new schools and, wrangling with each other over the most important matters of speculation, bring it about that their pupils hold conflicting views. The result is also that their minds, vacillating throughout their lives and unable to believe at all with firm conviction, simply wander in confusion. Anyways, it is true that, if a man were to examine carefully the most famous schools of the philosophers, he would find them differing from one another to an extreme degree and maintaining opposite opinions regarding the most fundamental tenets.

[System for interpreting the stars]

(2.30) Now, as the Chaldeans say, the world is by its nature eternal, and neither had a first beginning nor will at a later time suffer destruction. Furthermore, both the disposition and the orderly arrangement of the universe have come about through divine providence. Today whatever takes place in the heavens is in every instance brought to pass, not in a haphazard way, nor as a result of any spontaneous action, but by some fixed and firmly determined divine decision. (2) Since they have observed the stars over a long period of time and have noted both the movements and the influences of each of them with greater precision than any other men, they predict to humankind many things that will take place in the future.

[Five planets as “interpreters”]

(3) But above all in importance, they say, is the study of the influence of the five stars known as planets, which they call “interpreters” (hermeneis)​ when speaking of them as a group. But, if referring to them individually, the one named Kronos​ by the Greeks, which is the most conspicuous and presages more events and events that are of greater importance than the others,​ they call the star of Helios. Whereas the other four they designate as the stars of Ares, Aphrodite, Hermes, and Zeus,​ as do our astrologers. (4) The reason why they call them “interpreters” is that whereas all the other stars are fixed and follow a singular circuit in a regular course, these five alone, by virtue of following each its own course, point out future events, thus interpreting to humankind the design of the gods.

For sometimes by their risings, sometimes by their settings, and again by their colour, the Chaldeans say, they give signs of coming events to such as are willing to observe them closely. (5) For at one time they show forth mighty storms of winds, at another excessive rains or heat, at times the appearance of comets, also eclipses of both sun and moon, and earthquakes, and in a word all the conditions which owe their origin to the atmosphere and work both benefits and harm, not only to whole peoples or regions, but also to kings and to persons of private station.

[Thirty stars as “counselling gods” and the twelve gods that form the signs of the zodiac]

(6) Under the course in which these planets move are situated, according to them, thirty stars,​ which they designate as “counselling gods.” Among these, one half oversee the regions above the earth and the other half those beneath the earth, having under their purview the affairs of humankind and likewise those of the heavens. Every ten days one of the stars above is sent as a messenger, so to speak, to the stars below, and again in like manner one of the stars below the earth to those above, and this movement of theirs is fixed and determined by means of an orbit which is unchanging forever. (7) Twelve of these gods, they say, hold chief authority, and to each of these the Chaldeans assign a month and one of the signs of the zodiac, as they are called. Through the midst of these signs, they say, both the sun and moon and the five planets make their course, the sun completing his cycle in a year and the moon traversing her circuit in a month.

[Predictions for people]

(2.31)  Each of the planets, according to them, has its own particular course, and its velocities and periods of time are subject to change and variation. These stars it is which exert the greatest influence for both good and evil upon the birth of men. It is chiefly from the nature of these planets and the study of them that they know what is in store for humankind. (2) They have made predictions, they say, not only to numerous other kings, but also to Alexander, who defeated Darius, and to Antigonos and Seleukos Nikator who afterwards became kings, and in all their prophecies they are thought to have hit the truth. But of these things we shall write in detail on a more appropriate occasion. (3)  Moreover, they also foretell to those who are not rulers what will befall them, and with such accuracy that those who have made trial of them marvel at the feat and believe that it transcends the power of man.

[Twenty-four other stars, half in north and half in south]

(4) Beyond the circle of the zodiac they designate twenty-four other stars, of which one half, they say, are situated in the northern parts and one half in the southern, and of these those which are visible they assign to the world of the living, allow those which are invisible they regard as being adjacent to the dead, and so they call them “judges of the universe.” (5) Under all the stars mentioned so far, the moon, according to them, takes her way, being nearest the earth because of her weight and completing her course in a very brief period of time, not by reason of her great velocity, but because her orbit is so short.

[Chaldean system’s strengths and weaknesses in comparison with Greek concepts]

(6) They also agree with the Greeks in saying that the moon’s light is reflected and that her eclipses are due to the shadow of the earth. Regarding the eclipse of the sun, however, they offer the weakest kind of explanation, and do not presume to predict it or to define the times of its occurrence with any precision. (7) Again, in connection with the earth they make assertions entirely peculiar to themselves, saying that it is shaped like a boat and hollow, and they offer many plausible arguments about both the earth and all other bodies in the firmament, a full discussion of which we feel would be alien to our history. (8) A person might nonetheless appropriately maintain that the Chaldeans have of all men the greatest grasp of astrology, and that they devoted the greatest diligence to studying astrology. (9) But as to the number of years which, according to their statements, the order of the Chaldeans has spent on the study of the bodies of the universe, a man can scarcely believe them, for they reckon that, down to Alexander’s crossing over into Asia, it has been four hundred and seventy-three thousand years, since they began in early times to make their observations of the stars. (10) So far as the Chaldeans are concerned we shall be satisfied with what has been said, that we may not wander too far from the matter proper to our history. . .

[For Diodoros’ subsequent discussion of the Indians, go to this link].


[Chaldeans predict Alexander of Macedon’s death despite Greek wise men’s contrary arguments, ca. 324 BCE]

(17.112) After the conclusion of his war with the Kossaians, Alexander set his army in motion and marched towards Babylon in easy stages, interrupting the march frequently and resting the army.​ While he was still three hundred stadium-lengths from Babylon city, those called Chaldeans, who have gained a great reputation in astrology and are accustomed to predict future events by a method based on age-long observations, chose from their number the eldest and most experienced. By the configuration of the stars they had learned of the coming death of the king in Babylon, and they instructed their representatives to report to the king the danger which threatened. They told their envoys also to urge the king that he must under no circumstances make his entry into the city and that he could escape the danger if he re-erected the tomb of Belos which had been demolished by the Persians,​ but he would have to abandon his intended route and pass by the city.

The leader of the Chaldean envoys, whose name was Belephantes,​ was not bold enough to address the king directly but secured a private audience with Nearchos, one of Alexander’s Friends, and told him everything in detail, requesting him to make it known to the king. When Alexander, accordingly, learned from Nearchos about the Chaldeans’ prophecy, he was alarmed and more and more disturbed, the more he reflected upon the ability and high reputation of these people. After some hesitation, he sent most of his Friends into Babylon, but altered his own route so as to avoid the city and set up his headquarters in a camp at a distance of two hundred stadium-lengths away.

This act caused general astonishment and many of the Greeks came to see Alexander, notably among the philosophers Anaxarchos.​ When they discovered the reason for his action, they plied him with arguments drawn from philosophy and changed him to the degree that he came to despise all forms of divination (mantikē), and especially that which was held in high regard by the Chaldeans. It was as if the king had been wounded in his soul and then healed by the words of the philosophers, so that he now entered Babylon with his army. As on the previous occasion,​ the population received the troops hospitably, and all turned their attention to relaxation and pleasure, since everything necessary was available in profusion.

These were the events of this year. . . . [omitted remaining narrative including Alexander’s death at Babylon].


[Chaldeans predict Antigonos’ death, ca. 316 BCE]

(19.55) . . . But then the Chaldeans came to Antigonos [in the midst of his contention with Seleukos, the satrap of Babylon, ca. 316 BCE] and foretold that if ever he let Seleukos escape from his hands, the consequence would be that all Asia would become subject to Seleukos, and that Antigonos himself would lose his life in a battle against him. At this, Antigonos repented his former course and sent men to pursue Seleukos. However, after tracking him for a certain distance, they returned with their mission unaccomplished. Although Antigonos was accustomed to despise prophecies of this kind on other occasions, he was troubled considerably at this time, being disturbed by the reputation of the men, for they are reputed to possess a great deal of experience and to make most exact observations of the stars. Indeed they declare that for many thousands of years the study of these matters has been pursued among them. It is also believed that they foretold to Alexander, that, if he entered Babylon, he would die [see passage above]. And just as was the case with the prophecy about Alexander, it came to pass that this prophecy in regard to Seleukos was fulfilled according to the assertion of these men.


Source of the translation: C. H. Oldfather, Diodorus Sicilus: Library of History, volumes 1-6, LCL (Cambridge, MA: HUP, 1935-1952), public domain (copyright not renewed, passed away in 1954), adapted by Victoria Muccilli and Harland.

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