H.G.M. Williamson once wrote of this problem:1
No fully satisfactory explanation has been offered as to why [Darius] is called 'the king of Assyria'.
That hasn't stopped people trying, of course.2 Certain possibilities come to the fore:
- It's fairly clear that the succession of empires that is so clear to us had its hazy edges in antiquity.3
- There is another instance of this kind of error in Judith 2:1 of the Babylonian king, Nebuchadnezzar:4
...there was talk in the house of Nebuchadnezzar, king of the Assyrians, that he should be avenged on all the land...
Joseph Blenkinsopp has a brief but helpful summary of other suggestions:5
- scribal error [although the textual evidence for this is lacking];
- the supposition that "the Persian kings were, in a certain sense, the successors of the Assyrians";
- or "perhaps 'Assyria' could simply stand for Mesopotamia";
- or this was a function of later usage [like the "historical confusion" noted above].
To these Blenkinsopp adds his own suggestion -- which may count in some sense as "theological" -- that the account here is echoing "the account of Hezekiah's passover":
the allusion in the latter to the remnant which has escaped from the ahnd of the king of Assyria (2 Chron. 30:6) may well have been in the writer's mind as he brought his story of the return and restoration to a close.
Blenkinsopp doesn't note here that this little passage (Ezra 6:19-22) comes at the very point at which the book of Ezra switches back to Hebrew after a lengthy stretch in Aramaic (runs from 4:7 to 6:18). Fleishman (see note 2) does note this, and develops Blenkinsopp's view.
Summary - there's no certain explanation, then, but some very good educated guesses.
- In his article, "The Composition of Ezra i-vi", Journal of Theological Studies 34 (1983): 1-30 (quote from p. 22 n. 54).
- There's a nice little catalogue of earlier solutions listed by Joseph Fleishman, "An Echo of Optimism in Ezra 6:19-22", Hebrew Union College Annual 69 (1998): 15-20 (see pp. 21-22).
- Nicely illustrated by L.L. Grabbe, "Josephus and the Reconstruction of the Judean Restoration", Journal of Biblical Literature 106 (1987): 231-246.
- This reference, along with some less striking but related ones, is noted by L.W. Batten, A critical and exegetical commentary on the Books of Ezra and Nehemiah (ICC; Edinburgh: T & T Clark, 1913), pp. 153-4.
- In his Ezra-Nehemiah: A Commentary (Westminster/John Knox, 1988), pp. 133