When did equus regain its first U?

Question

I learned from this question about sequundus > secundus that -quus was in fact pronounced as if it was -cus. However, words like equus were not spelled as ecus, since most oblique cases would still have the original stem equ- since qu>c only occurred before a u. That is, equus was pronounced ecus but was spelled equus by analogy.

I would assume that at some point the spelling equus caused the pronunciation to become equus instead of ecus again. At least this is the case in the contemporary Finnish pronunciation. I have no idea when this change happened, other than "somewhere between imperial Rome and present day Finland", but I suspect this equus pronunciation (as opposed to ecus) was not unusual in some form of medieval or later Latin. Do we know when — if ever — this change took place? When was equus pronounced as equus and no longer ecus? Any examples or a terminus ante/post quem are most welcome; I don't expect anyone to be able to point a precise point in time.

Answer 1

My guess is, the answer for eqvus will be earlier than the answer for most other words. In the Classical period eqvus was a common, everyday word, but at some point in Vulgar Latin it was displaced by the Gaulish loan caballus. Once eqvus wasn't used in day-to-day speech, it would be easy for a spelling pronunciation to take over.

In general, though, I'd date these sorts of spelling pronunciations to the European Renaissance. That's the point where Latin somewhat stopped evolving naturally: Desiderius Erasmus and others realized that their Latin pronunciation had been heavily affected by Romance, and decided to "purify" it. Erasmus in particular wrote a long treatise on how the pronunciation of Greek and Latin had degraded, and listed ways to make it Latin again: distinguishing ae from ē, removing palatalization before i, and so on.

Before Erasmus, I wouldn't expect any Romance-speaker to go from the easier /ku/ to the more difficult /kwu/ (except through spelling pronunciation for an obscure word). But once there was a conscious attempt to imitate the gold standard of Cicero and Vergil—that is, to imitate specifically the written words of Cicero and Vergil—less natural but more prestigious pronunciations make complete sense.