Did queen even mean just wife or dame? I'm going to be lengthy; forgive me.

Idling through Asimov's Guide to Shakespeare, I noticed his gloss on the Romeo and Juliet passage where Mercutio speaks of "Queen Mab", who brings dreams:

Mer. O, then I see Queen Mab hath been with you.
She is the fairies' midwife, and she comes …
Through lovers' brains, and then they dream of love …
Rom. Peace, peace, Mercutio, peace! / Thou talk'st of nothing.
Mer. True, I talk of dreams.

Asimov says, Queen Mab need not be considered a fairy queen [in the modern sense]. She is the fairies' "midwife"; that is, she helps men and women give birth to dreams, and this is no task for queeen. Here, in all likelihood, "Queen" is used in its original sense of "woman", and to speak of "Queen Mab" would be something like speaking of "Dame Mab"or "Mistress Mab." The wold "queen" early split into two forms: one of them, "quean,," degenerated to mean a degraded woman, a harlot; the other, "queen," rose to mean an elevated woman, the wife of a king. "Queen," in its ordinary original sense, neither depressed nor elevated, vanished altogether.

Interesting – but OED [quoted below] seems to say that "queen" had lost its "ordinary, non-royal" sense centuries before Shakespeare's time. So what's going on here? Is Asimov wrong in thinking that "Queen Mab" refers to an ordinary, non-royal woman? Is he right in thinking so – but the name comes from the centuries-before-Shakespeare days? Or is OED wrong, or not saying what I think it says?

Help!

Without hauling Asimov's volume out, it seems to me that "queen" is being used to signify a potentate, else how could she bring dreams? She may just be "the sandman" to us nowadays, but when one considers the significance of dreams in many Shakespeare plays, it suggests she's a regal, not a commoner in your cited passage. Also, dreaming of love is, for a romantic, a regal actifity!

Queen is related to English quean, an archaic word for prostitute, Greek γυνη gunē 'woman' (whence our gynocracy, gynocology), Irish ban (whence our banshee), Swedish kvena, from PIE *gwen-

This post quotes OED; my comments are in brown type.

queen [OE. cwén str. fem. = OS. quân (once in Hel.), ON. kvæn (also kván), Goth. qêns woman:--OTeut. *kwni-z f., an ablaut-var. of the stem represented by OE. cwene QUEAN. The gen. sing. quene (OE. cwéne) is occas. found in ME.]
. . .Even in OE., cwén was app. not an ordinary term for ‘wife’, but was applied only to the wife of a king [emph. added; notice that OED is hedging. Others more able than I can judge if the earliest quotes bear this out. In the quotes, since eth and thorn don't work in unicode, I'm using ₤ and € respectively to represent them.]
c893 K. ÆLFRED Oros. I. ii. §2 Æfter his dea₤e Sameramis his cwen [L. uxor] fengc..to €æm rice.
c893 K. ÆLFRED Oros. I. x. §3 €ær wear₤ Marsepia sio cwen ofsla₤en.
c893 O.E. Chron. (Parker MS.) an. 888 Æ€elswi€ cuen, sio wæs Ælfredes sweostor cyninges.
a900 CYNEWULF Christ 276 Seo clæneste cwen ofer eor€an.
c825 Vesp. Psalter xliv. 10 Ætstod cwoen [L. regina] to swi₤ran ₤ire.

quean [OE. cwene wk. fem. = OS. quena (MDu. quene, Du. kween a barren cow), OHG. quina, quena, ch(w)ena, ON. kvenna, kvinna (gen. pl.), Goth. qino woman:--OTeut. *kwenon-, a lengthened form of the stem which appears in Zend gena, Gr. , OSl. and Russ. ená, OIr. ben, repr. a common Aryan type *gwena: cf. QUEEN. [I give up trying to represent all the characters!]
. . .In ME. the word was distinguished from QUEEN by its open e, which in the 14-15th c. was sometimes denoted by the spelling with ei or ey, and later (as in other words of the class) by ea.

quote: 'Queen' is related to English 'quean', an archaic word for prostitute

Yes -- I'm asking about the details of the relationship.

Is it correct that there was at one time a single word (now vanished) meaning 'woman' or 'wife' in a neutral sense, which ultimately spawned two separate words, one of them (modern queen) for a very high-level woman and the other (quean) for a degraded one? (How remarkable that a single word should, over time, undergo both perjoration and amelioration!)

If so, when did these changes occur, and in what language; did they predate old English? When did the elevated and debased meanings arise, and when did the neutral meaning die out? (Had it died out by Shakespeare's time?)

I'm asking about the details of the relationship.

There were two words in Old English, and there were two words in Gothic, the oldest recorded Germanic language. In Old English, cwene 'quean, impudent woman, hussy' was replaced by another word for 'woman', wifmann, literally 'wife-man', whence our woman, cf. Gothic qino 'woman, female', both from Proto-Germanic *kwen-ōn-; Old English cwén 'wife; queen (i.e. king's wife)', cf. Gothic qens 'wife', from Proto-Germanic kwēn-i- 'wife'. So, they are assumed to have been two different forms of the same PIE root *gwen-ā- 'woman'. The differences probably had to do with accent (stress) and suffix.

Things to ponder: (1) in no other Germanic language is the word for queen, the wife of a king or ruler in her own right; (2) in German, Weib 'crone, hag; dame, broad' has taken on a pejorative sense, cf. Russian žena.

quote:

OED ... seems to say that "queen" had lost its "ordinary, non-royal" sense centuries before Shakespeare's time.

Maybe, but the person known as Queen Mab existed in folklore long before Shakespeare.

arnie, the net confirms that Mab (in various spellings) long antedates Shakespeare. But I couldn't find anything indicating that she was called a queen until Shakespeare.

That's far from dispositive, because almost everything the net says is in connection with Shakespeare and later writers, with darn little discussion of her earlier presence in myth. I'm quite willing to take the "queen" part faith, knowing your encyclop(a)edic knowledge , but if you happen to have a source at your fingertips, let me know. Thanks.