I'll repost an answer from two years ago which comes from a thread where myself, /u/antiquarianism, and /u/sagathain among others discussed this in depth.

I don't recall seeing anything in the two big sleep journals in the couple of years since, and the only major new article I found in a very brief search - it's worth keeping in mind you're asking this on a holiday - was a 2021 metaanalysis that bears this out in both the lit (the most recent paper cited was 2020) along with the conclusion, which continues to suggest modern era polyphasic sleep generally leads to a lower quality of sleep by most metrics.

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How's this for an answer: some likely did, but others likely didn't.

One caveat: I'm coming at this from a slightly different angle, which is familiarity with the history of sleep research rather than that of the eras you're asking about - so it's one reason I'm hopeful some of the medievalists and early modernists here chime in as I'm quite curious what (if any) debate there's been on this in their fields.

That said, the main contributor to noctural biphasic theory (versus biphasic in general, which can refer to daytime siestas as well) is a historian at Virginia Tech by the name of Roger Ekrich, who back in 2004 wrote a survey of nocturnal habits throughout the world, At Day's Close - Night in Times Past. While much of the book dealt with various societal oddities throughout Europe at night, the one that caught the most traction was his analysis of literature that suggested that pre-industrial age humans slept somewhat differently than we do today:

Until the close of the early modern era, Western Europeans on most evenings experienced two major intervals of sleep bridged by up to an hour or more of quiet wakefulness. In the absence of fuller descriptions, fragments in several languages in sources ranging from depositions and diaries to imaginative literature give clues to the essential features of this puzzling pattern of repose. The initial interval of slumber was usually referred to as “first sleep,” or, less often, “first nap” or “dead sleep.” In French, the term was premier sommeil or premier somme, in Italian, primo sonno or primo sono, and in Latin, primo somno or concubia nocte. The succeeding interval of sleep was called “second” or “morning” sleep, whereas the intervening period of wakefulness bore no name, other than the generic term “watch” or “watching.” Alternatively, two texts refer to the time of of “first waking.”

Both phases of sleep lasted roughly the same length of time, with individuals waking sometime after midnight before returning to rest. Not everyone, of course, slept according to the same timetable. The later at night that persons went to bed, the later they stirred after their initial sleep; or, if they retired past midnight, they might not awaken at all until dawn. Thus in “The Squire’s Tale” in The Canterbury Tales, Canacee slept “soon after evening fell” and subsequently awakened in the early morning following “her first sleep”; in turn, her companions, staying up much later, “lay asleep till it was fully prime” (daylight). William Baldwin’s satire Beware the Cat recounts a quarrel between the protagonist, “newly come unto bed,” and two roommates who “had already slept” their “first sleep.”

Men and women referred to both intervals as if the prospect of awakening in the middle of the night was common knowledge that required no elaboration....

Ekrich goes on to review a reasonable amount of contemporary literature that suggested this was fairly commonplace and to note a series of early 1990 experiments by Thomas Wehr at the NIH that artificial light appeared to be one of the primary culprits responsible for disturbing biphasic sleep, along with a walk through what people actually used to do in the middle of the night.

So far, so good, and Ekrich continued this research across cultures and published in several fairly well respected journals, lectured in front of medical faculties, and even is on the board of the main publication of the National Sleep Foundation.

Except then in the early 2010s, his theory took a bit of a hit. Several anthropologists got interested in the subject, and realized that their field provided a fantastic opportunity to check on this with current day isolated preindustrial societies. The result was a 2015 paper, Natural sleep and its seasonal variations in three societies, that went a step further and put Actiwatches on current day pre-industrial societies near the equator - and noted precisely none of them experienced biphasic sleep.

Ekrich's response is quite interesting, and in a sign of the importance his theories had gained it appeared in what's considered the main sleep research journal, Sleep. But the relevant part for your question is this portion:

As I have recently written at length, consolidated sleep to which the industrialized world aspires, if not always successfully—due perhaps to the persistence of this once dominant pattern—is for Western societies a remarkably youthful form of sleep, a product not of the primeval past but of forces grounded in technology (artificial illumination) and shifting cultural attitudes toward sleep over the course of the Industrial Revolution. This is not to argue that segmented sleep has been the predominant pattern of sleep among all preindustrial peoples in the non-Western world. [emphasis added]

So, the best answer is probably that it depended on the population and possibly where they're located, along with how much artificial light they were exposed to.

I think this question would also be at home in r/AskAnthropology. It deserves a crosspost!