I first cite the definitions of "but" as an adverb or preposition:
adverb : no more than; only.
Preposition: except; apart from; other than:
Could someone please elucidate/explicate but only below?
Does it mean "only", "all but", "nothing but", ... ? Also, is the "but" redundant?
Please also illuminate how you sussed/unravelled the meaning.
These, hearing first of the commotions which began about the same time in the other parts to broil, as in Oxfordshire, Yorkshire, and especially in Norfolk and Suffolk, began to take therein some courage, hoping that they should have well fortified the same quarrel. But afterwards, they, perceiving how the mischievous mutterings and enterprises of their conspiracy did suddenly fail, either being prevented by time, or repressed by power; or that their cause, being but only about plucking down of inclosures, and enlarging of commons, was divided from theirs, so that either they would not or could not join their aid together, then began they again to quail, and their courage to abate. Notwithstanding, forasmuch as they had gone so far that they thought there was no shrinking back, they fell to new devices and inventions, for the best furtherance of their desperate purposes.
I referenced: 1: Rephrasing of "All But"
2: [ All + Noun + But ] vs [ All But as an Idiom
3: Vincent McNabb's Comment: All But = Everything Except.
4: "Anything but" vs "Everything but" vs "Nothing but"
5: Two meanings of "But": Inclusion or Exclusion ?
I. If there's a whole and a part, then but imports inclusion: but = only.
II. If there's only a whole (I daresay but a whole), then but connotes exclusio = except.
7: Only vs But Only