The Achaemenid empire used deportation selectively, as a punishment for rebellion and a means of placing useful populations where the crown wanted them. Herodotus records that after crushing the Ionian revolt in 494 BCE the Persians killed or enslaved the Milesians and settled the survivors at Ampe near the mouth of the Tigris; that in 490 BCE the Eretrians, who had aided the revolt, were carried off to Ardericca in Elam, where a distinct community was still recognisable centuries later; that the Barcaeans of Cyrenaica were resettled in a Bactrian village; and that Cambyses removed 6,000 Egyptians with their king and many artisans to Susa. Encyclopaedia Iranica notes that Achaemenid deportees were given land, kept their languages and religions, and were subject to taxation and restrictions on movement rather than being enslaved outright. The Persepolis administrative tablets record large multi-ethnic labour forces in the imperial heartland, consistent with the practice, though the Greek narrative sources remain the only origin for the individual episodes and figures.
Achaemenid kings from Cambyses to Darius I deported the populations of defeated cities — Barca in Cyrenaica, Miletus in Ionia, Eretria in Euboea and groups of Egyptians — and resettled them in the Iranian and Central Asian interior
There is no census basis for a total. The affected communities were single cities, each plausibly holding a few thousand to some tens of thousands of people on archaeological and textual grounds — Herodotus is the main source and his numbers are rhetorical rather than statistical — and the deportations were scattered across three decades and several satrapies, so no defensible aggregate denominator can be reconstructed.
No usable range. Herodotus reports the killing of most Milesian men and the burning of the city and its temple in 494 BCE, and the burning of Eretria in 490, but gives no counts; the deportations themselves were intended to preserve the population for resettlement.
Herodotus records the burning of Miletus and its sanctuary at Didyma and the destruction of Eretria's temples before the deportations, as summarised on Livius.org.
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