Everything about "pox leber" as a minced oath, and an earlier source.

[Koen G]

The OCR Fastnachtspiele Torsten touched upon in the other thread contain an interesting form of "pox", which seems intermediate to me:
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"Die meidt bald bey ir selber schwur
Samer pox hur so glaubet mir"

I think this translates to, keeping word order:

"The maid soon to her self swore
So me God .... believe me"

I'm unclear about the word "hur", this might be an OCR error. Maybe hör, "so hear me God"?

If you look back at the first post of this thread, the priest was complaining about people trying to evade proper testimony by saying "sam mir pox" instead of "Gott". So this attestation is an example of that, in the internal monologue of a lower class individual. This kind of language would have amused the audience as a recognizable caricature of the speech mannerisms of farmers, maids etc.