Subjunctive Mood in Past Tense, Historical, Narratives

I have a question about use of the subjunctive in past tense narratives.

The quoted passage is from Keith Thomas’s Religion and the Decline of Magic, a sort of cultural history of England in the sixteenth and seventeenth centuries. The excerpt regards an obscure zealot, William Hacket, but I’m quoting it for its last sentence, a subjunctive statement:

Hacket had already been roughly treated in various English provincial towns, and his prominence in 1591 sprang from his association with two Puritan gentlemen, Edmund Copinger and Henry Arthington .... [to the former of whom] Hacket ... was both King of Europe and the Angel who would come before the Last Judgement to separate the sheep from the goats; if he were imprisoned, the bolts would magically fall off.

So of course this is a “were” conditional. Its reference is to undefined time, or more precisely not to time at all but to the hypothetical. But if Thomas had written the sentence in past time, something like

If he was imprisoned, the bolts magically fell off

Or

If he was imprisoned, the bolts would magically fall off

should our understanding of it be changed? And would it be preferable to cast it in a subjunctive mood, or in a past, indicative one concerned with past eventualities?

Solution 1:

To maintain the subjunctive and use the past tense in this case (while keeping the same wording of were), you have to add several verbs in the first part of the sentence, as well as changing the tense in the second part of the sentence.

Present-tense subjective:

If he were imprisoned, the bolts would magically fall off.

Past-tense subjunctive:

If he were to have been imprisoned, the bolts would have magically fallen off.

Since it's now the past tense rather than the present tense, it does indeed change the meaning of the sentence. As for whether the indicative is better than the subjunctive, that's just a matter of opinion.