On a recent language log post, Mark Liberman noted, in passing, that when Queen Gertrude observes that the Player Queen “doth protest too much, me thinks,” this does not, as modern readers usually assume, mean that the Player Queen is objecting so loudly and forcibly that the opposite of what she is saying is likely true, but, rather, that she is promising to do too much (i.e., by promising to never remarry if she is widowed). Protest, is said to have meant, in Shakespeare’s day, a solemn declaration, a vow, or a promise. Liberman quotes a Wikipedia article for this, and Wikipedia cites this article from e-notes.com, which, as far as I can tell, does not, itself, have any citations. The Wikipedia article suggests, and the e-notes article expressly states, that the “object/reject/denounce” sense of “protest” did not arise until after Shakespeare’s time. FWIW, even if we assume for the sake of argument that “protest” had taken on a sense of “disagree with” by Shakespeare’s age, I am persuaded that Gertrude was using the word “protest” in the solemn declaration / vow sense based on the context in which she used it. But I can’t help but wonder if Shakespeare was making use of both the “object to” and “solemnly declare” senses of “protest”, and making a pun of sorts. Of course, for that to be a possibility, the “object to” sense of “protest” would have to have existed at that point.
Another LL commenter noted that this sense of “protest” (vow, promise, declaration) also likely was the basis for “Protestant”: the point of the term was that the Protestants were affirming their belief in the validity of Luther’s theses, rather than objecting to or denouncing the teachings or authority of the Catholic Church.
The latter claim, I think, is not entirely right. At least per dictionary.com, “Protestant” arose (in English, anyway) in 1539, and it originally referred to the German princes and free cities who declared their dissent from the Diet of Speyer, which, itself, denounced Luther. “Protestant” later expanded to mean any Lutheran, then any adherent of the Reformation in Germany, then to any member of the Reformation. So, the term Protestant referred to somebody who had solemnly declared something (namely, dissent from the Diet of Speyer) and also to a person who had objected to something (namely, the Diet of Speyer). But which would have been understood to be the driving force behind the term: the public support for something (which was only coincidentally a rejection of something in this case) or the denouncing of something (which, in this case, was done publicly)?
The dictionary.com entry for “protest” seems to support e-notes’s claim that protest, as in “object to”, arose after Shakespeare’s day. It says that “protest” is first recorded in English in 1340 as a noun meaning a “solemn declaration”, and that the verb is attested to in 1440 as “to declare or state formally.” The meaning “statement of disapproval” is said to be first recorded in 1751. However, it seems to me that “statement of disapproval” is a fairly specific gloss on the term, and I can’t help but wonder if “protest” could have taken on a looser sense of “disagree with” at some point before 1751.
A final speculative note: is it possible that “Protestant” helped nudge “protest” along in taking on a sense if “disagree with”, given the former’s historical referent (an objection to the Diet of Speyer)?