Interpretatio graeca
The ancient practice of naming a foreign god by the Greek god taken to be the same — Amun as Zeus, Osiris as Dionysus, Isis as Demeter — first documented in Herodotus's account of Egypt; the Roman counterpart is the interpretatio romana.
Why this wins its question: Definitions of the term usually stop at Tacitus. This one binds each Egyptian–Greek equivalence to its exact sentence in Herodotus, so an agent can quote the witness instead of the dictionary.
Key takeaways
- Herodotus is the oldest surviving witness: Amun = Zeus, Osiris = Dionysus, Isis = Demeter, Horus = Apollo, Bubastis (Bastet) = Artemis.
- He treated the equivalence as genealogy (the names came from Egypt), not as metaphor.
- Every cross-pantheon `equivalent_of` relation in this corpus is an interpretatio, and each names the ancient text that made it.
Claims
Every assertion below is bound to registered sources and carries its own confidence. Weight them; do not treat the page as uniformly authoritative.
Herodotus explicitly equates Egyptian and Greek gods by name: "the Egyptians call Zeus 'Amon'" (Hdt. 2.42.5), Osiris "is Dionysus" (Hdt. 2.42.2), Isis "is Demeter in the Greek language" (Hdt. 2.59.2), and "Apollo is Horus, Demeter Isis, Artemis Bubastis" (Hdt. 2.156.5).
For Herodotus the identification runs deeper than translation: he claims "the names of nearly all the gods came to Greece from Egypt", excepting Poseidon, the Dioscuri, Hera, Hestia, Themis, the Graces and the Nereids (Hdt. 2.50.1–2) — a historical thesis modern scholarship does not accept, but the earliest statement of the method.
Herodotus explains the ram-headed images of Amun with a Greek myth transposed: Zeus showed himself to Heracles wearing the head and fleece of a ram, "and it is from this that the Egyptian images of Zeus have a ram's head" (Hdt. 2.42.3–4).
The modern term interpretatio graeca (and its pair interpretatio romana, from Tacitus's Germania 43) names this practice of reading other peoples' gods as local versions of one's own pantheon.