Chaldaeans

kal-DEE-unz

Definition

The word "Chaldaeans" carries two meanings. In its narrow, literal sense it names a Semitic-speaking people of southern Mesopotamia — the Akkadian Kaldu — who supplied several Neo-Babylonian ruling dynasties from the 9th century BCE. But from the Hellenistic period onward, Greek and Roman writers used "Chaldaean" loosely as a job label for any astrologer trained in the Babylonian style, whatever their actual ethnic background. The Greeks believed astrology itself had come from Babylonia, and the word carried that belief.

In Tradition

Historians of Hellenistic astrology read "Chaldaean" as a marker of where a method came from, not of who someone was. James Holden traces the habit to Berosus and other Babylonian teachers who first carried their art to Greek-speaking audiences; he notes that "Chaldean" spread as a widespread label for astrologers across the Greco-Roman world, reflecting how plainly people acknowledged the Babylonian roots of the discipline.

In Practice

When you read "Chaldaean" in a Greek or Latin author — Diodorus, Strabo, Cicero, Pliny, Tacitus — it usually means someone who practised Babylonian-style astrology, not a member of the Semitic people. The Roman decrees that expelled "Chaldaeans" (notably under Tiberius in 16 CE, and again later) targeted working astrologers, not an ethnic group. Modern scholars tell the two senses apart by context: the people-and-politics sense shows up alongside Neo-Babylonian dynasties, while the astrologer sense shows up alongside horoscope-casting or omen-reading.

Historical Origin

The astrologer sense is attested by Berosus around 280 BCE, whose school on Kos passed Babylonian astronomy and pre-horoscopic omen-lore to a Greek-speaking audience. The Roman decrees expelling "Chaldaei" begin under Tiberius — recorded by Tacitus, *Annals* II.32, in 16 CE — and recur afterward. The term is treated in detail in Holden, *A History of Horoscopic Astrology* (1996/2006); Barton, *Ancient Astrology* (1994); and Rochberg, *The Heavenly Writing* (2004).

Further Reading

  • James H. Holden, A History of Horoscopic Astrology
  • Francesca Rochberg, The Heavenly Writing: Divination, Horoscopy, and Astronomy in Mesopotamian Culture