Why is it correct to say "it later came to pass" instead of "it came to pass later"? What is the rule for this placement?
There is no particular ironclad rule that I can think of, but the first sounds immeasurably better to my ear.
- It later came to pass that. . . .
- It came later to pass that. . . .
- It came to pass later that. . . .
Both are perfectly grammatical.
To me the second construction is in general hugely more idiomatic English (It happened later). But the first form has a slightly literary or archaic feel, and so matches better with the literary phrase came to pass.
Neither is necessarily incorrect; I also can't imagine that one is necessarily worse, at least without knowing the context.
The semantic distinction between the two (putting aside the different poetic properties that StoneyB mentions) is a subtle one of emphasis.
- It later came to pass... This phrase is somewhat of an idiom in English, a familiar phrase. It recalls a story-telling tone, and expresses a segue as from one time period to another.
- It came to pass later... Here the later does (granted) feel a bit out of place, and as such the phrase seems to emphasize the later condition of whatever it is, rather than it itself.