“Some sources suggest that Berossos had, as it were, an international career as an astronomer. According to those sources, he left Babylon and migrated to the Greek world after the publication of his history.
Vitruvius states that he moved to the island of Cos and opened a school there (BNJ T 5a-b). Vitruvius also ascribes the invention of a specific type of sundial to Berossos (BNJ 680 T 5c).
Josephus agrees with the Roman architect that Berossos propagated Babylonian lore: he says that the Chaldaean was famed among those who were engaged in learning, because he published for the Greeks works on astronomy and on the philosophy of the Chaldaeans (BNJ 680 T3).
Pliny the Elder presents Berossos as the most important scholar of astronomy/astrology and adds that the Athenians honoured him with a statue with a gilded tongue because of his divine predictions (BNJ 680 T 6).
The historicity of these biographical data is subject to debate. Burstein and Verbrugghe / Wickersham accept the ‘second’ life of Berossos as historical. Schwartz rejects the testimony according to which Berossos opened a school on Cos, because he thinks it unlikely that the Babylonian priest would have abandoned his prebendary income in Babylon.
Some judge it impossible that Berossos would have migrated to an island that was under control of the Ptolemies, bitter enemies of the Seleucids. These are not convincing arguments to discard the historicity of the biographical information. In itself, it is not impossible that Berossos migrated to the west and taught Babylonian astronomy / astrology.
The question of historicity should, however, be connected with the question of whether the astronomical / astrological fragments transmitted under the name of Berossos are authentic (BNJ 680 F 15-22). As Kuhrt and the present author have shown, these fragments reflect Greek, not Babylonian doctrines and are, therefore, not authentic.
Babylonians believed that gods grouped the stars into constellations and gave them names, not men, as BNJ 680 F 17 states. There are no indications that they believed in a cyclical destruction of the universe by fire or water (BNJ 680 F21), whereas this was a popular doctrine of the Stoics.
Several ancient authors ascribe a lunar theory to Berossos that explains the lunar phases and lunar eclipses (BNJ 680 F 18-20). In short, this theory asserts that the moon has its own light and consists of a luminous hemisphere and a dark one. It rotates around its own axis. The lunar phases are the result of the attraction of the moon’s luminous hemisphere by the sun, which depends on the distance between both celestial bodies.
The closer the moon is to the sun, the more the fiery hemisphere is attracted by the latter and is turned toward it. The moon’s dark side is correspondingly turned towards the earth. So far, there is no evidence in the cuneiform sources that this theory, which other classical authors attribute to the Babylonians in general (Lucretius, De rerum natura, 720-7 and Apuleius, De deo Socratis, 1.1), has a Babylonian background; it seems that it is a Greco-Roman creation.
Finally, no astrological cuneiform texts have been preserved that determine the maximum lifetime of a human being by calculating the sum of the rising times of the zodiacal sign in which that person was born, and of the two subsequent signs (BNJ 680 F22).
On the other hand, it was a popular doctrine in Greek and Roman astrology. Pliny the Elder, who mentions Berossos’ calculation (BNJ 680 F22a), ascribes the origin of this theory not to the Babylonians, but to two Egyptians Nechepso and Petosiris, themselves fictitious characters.”
Geert de Breucker, “Berossos: His Life and Work,” from Johannes Haubold, Giovanni B. Lanfranchi, Robert Rollinger, John Steele (eds.), The World of Berossos, Proceedings of the 4th International Colloquium on the Ancient Near East Between Classical and Ancient Oriental Traditions, Harrassowitz Verlag, Wiesbaden, 2013, 19-20.