What is called "religion" today was non-existent for people in the ancient and medieval worlds. There was ritual.
Modern Abstractions like "religion" hide ancient realities.
It was in the 16th and 17th century that the concept of "religion" as we know it was invented as a reified, abstract, monolithic, uniform, timeless, and universal "thing" that is found across time, cultures, and languages.
Holy texts such as the Bible or the Quran never identified people by their private transcendental/supernatural beliefs.
As this article HERE says, Ethan Shagan in his book The Birth of Modern Belief: Faith and Judgment from the Middle Ages to the Enlightenment says :
"..the biggest transformation in the history of religion in the West was not the rise of unbelief but the transformation of belief itself...
As Brent Nongbri has put it:
"Because of the pervasive use of the word religion in the cultures of the modern western world (the “we” here) we already intuitively know what religion is before we even try to define it: religion is anything sufficiently resembling modern Protestant Christianity…Most of the debates about whether or not this “ism” (Confucianism, Marxism, etc…) is really a religion boils down to the question of whether or not they are sufficiently similar to modern Protestant Christianity."
In fact in an absolutely fascinating subset of chapter two of his book entitled “The Invention of Religion Outside the West,” Cavanaugh over and over again points out that in notebooks and autobiographies of early missionaries in the modern period, there is constant amazement at indigenous peoples that they “had no religion.”[vii]
This as a claim was not equivalent to saying they were “godless,” or “heathen,” as one might expect. Instead it was a very genuine observation that they had no compartmentalization of culture whose pieces of which could be referred more or less one-to-one with what was becoming the modern picture of Protestant “religion.”
It thus became confusing for the missionaries, with their own notion of what “religion” was, to understand exactly what a “conversion” for these people would look like.
Thus, though this is a simplistic summary, pieces of indigenous cultures were arbitrarily broken out of and abstracted from the wholes which they previously were integrated with, to discern these peoples “religion.”
Cavanaugh cites the study of Derek Peterso regarding the Gikuyu people of Kenya:
"Religion was supposed to be an otherworldly belief system, a contract agreed upon by God and believer. This disembodied, propositional definition of religion was the template that allowed European intellectuals to make sense of the ideas of colonized subjects. By reducing difference to sameness, by disembodying subject's ideas and practices, comparative religion functioned as a strategy of intellectual control."
Or one more example, fun fact: There was no religion named “Hinduism,” until 1829. There were of course Hindus for much, much longer. Yet “Hindu” was a Persian term, used traditionally to refer to those on the far side of the Sindhu river. Writes Cavanaugh:
"The invention of Hinduism as a religion allowed for the differentiation of Hinduism from politics, economics, and other aspects of social life, and it also allowed for the distinction of Hinduism from other religions such as Buddhism, Sikhism, and Jainism. Such differentiation was not simply an improvement on the former system of classification, however, as if new terms suddenly allowed Indians to see what they had been missing before. To the contrary the use of the term religion has produced confusion and misdescription of the phenomenon of Indian life.
As Timothy Fitzgerald points out, the separation of religion from society in India is misleading in a context in which caste hierarchy, exchange of goods, ritual, and political power are densely intertwined.
Imagine No Religion: How Modern Abstractions Hide Ancient Realities by Carlin A. Barton is a superb book.
Other good books on the emergence of the concept “religion” are:
Before Religion: A History of a Modern Concept
‘Religion’ and the Religions in the English Enlightenment
The Territories of Science and Religion.
Barton writes :
"When we make the claim that there is “no religion” as we know it in the cultures we are describing, we can hear readers objecting: But that culture has gods and temples, holy days and priestly rules, so how can we say they have “no religion”? The point is not, as Nongbri emphasizes, that there weren’t practices with respect to “gods” (of whatever sort), but that these practices were not divided off into separate spheres from eating, sleeping, defecating, having sexual intercourse, making revolts and wars, cursing, blessing, exalting, degrading, judging, punishing, buying, selling, raiding and revolting, building bridges, collecting rents and taxes.
"When we make the claim that there is “no religion” as we know it in the cultures we are describing, we can hear readers objecting: But that culture has gods and temples, holy days and priestly rules, so how can we say they have “no religion”? The point is not, as Nongbri emphasizes, that there weren’t practices with respect to “gods” (of whatever sort), but that these practices were not divided off into separate spheres from eating, sleeping, defecating, having sexual intercourse, making revolts and wars, cursing, blessing, exalting, degrading, judging, punishing, buying, selling, raiding and revolting, building bridges, collecting rents and taxes.
We are not arguing that “religion” pervaded everything in those cultures or that people in those times and climes were uniquely “religious,” but that, as Nongbri makes clear, “[A]ncient people simply did not carve up the world in that way.”...It is in the disembedding of human activities from the particular contexts and aggregations found in many societies into one concept and named entity or even institution that we find the genealogy of the modem western notion of “religion.”
Just as people had intercourse of more or less the same varieties as today (if the pictorial evidence from antiquity can be relied on) and made babies (or not) but did not organize these practices and experiences into a category of “sexuality,” so too people sacralized and desacralized/desecrated, feared and revered and loved, made bonds and oaths, performed rituals, and told stories about gods and people without organizing these experiences and practices into a separate realm.
“Imagining no religion” does not mean that we imagine that people did not make gods or build temples, praise and pray and sacrifice, that they did not ask metaphysical questions or try to understand the world in which they lived, conceive of invisible beings (gods, spirits, demons, ghosts), organize forms of worship and festival, invent cosmologies and mythologies, support beliefs, defend morals and ideals, or imagine other worlds.” (4); the modern construct of religion is pretty much based on Christianity (7-8); “In the academic field of religious studies, the claim that religion is a modern invention is not really news” (8); “Nongbri has observed that despite decades of problematization of the notion of “religion,” “[I]t is still common to see even scholars using the word ‘religion’ as if it were a universal concept native to all human cultures. In ... the study of the ancient Mediterranean world, every year sees a small library’s worth of books produced on such things as ‘ancient Greek religion.”
Indeed, the number of scholars who begin their books on “Roman Religion” by asserting that they know that the term doesn’t fit Roman culture, but they will continue using it anyway “for convenience” is remarkable. Nongbri goes on to suggest that the reason for such self-contradiction is the lack of a coherent narrative of the development of the concept of religion, a lack that his book proposes to fill. Fitzgerald forthrightly argues that, “[R]eligion cannot reasonably be taken to be a valid analytical category since it does not pick out any distinctive cultural aspect of human life,” as opposed, for instance, to ritual that does but that also crosses boundaries between that which we habitually call “religion” in our culture and that which we habitually call the “secular.”
Just as people had intercourse of more or less the same varieties as today (if the pictorial evidence from antiquity can be relied on) and made babies (or not) but did not organize these practices and experiences into a category of “sexuality,” so too people sacralized and desacralized/desecrated, feared and revered and loved, made bonds and oaths, performed rituals, and told stories about gods and people without organizing these experiences and practices into a separate realm.
“Imagining no religion” does not mean that we imagine that people did not make gods or build temples, praise and pray and sacrifice, that they did not ask metaphysical questions or try to understand the world in which they lived, conceive of invisible beings (gods, spirits, demons, ghosts), organize forms of worship and festival, invent cosmologies and mythologies, support beliefs, defend morals and ideals, or imagine other worlds.” (4); the modern construct of religion is pretty much based on Christianity (7-8); “In the academic field of religious studies, the claim that religion is a modern invention is not really news” (8); “Nongbri has observed that despite decades of problematization of the notion of “religion,” “[I]t is still common to see even scholars using the word ‘religion’ as if it were a universal concept native to all human cultures. In ... the study of the ancient Mediterranean world, every year sees a small library’s worth of books produced on such things as ‘ancient Greek religion.”
Indeed, the number of scholars who begin their books on “Roman Religion” by asserting that they know that the term doesn’t fit Roman culture, but they will continue using it anyway “for convenience” is remarkable. Nongbri goes on to suggest that the reason for such self-contradiction is the lack of a coherent narrative of the development of the concept of religion, a lack that his book proposes to fill. Fitzgerald forthrightly argues that, “[R]eligion cannot reasonably be taken to be a valid analytical category since it does not pick out any distinctive cultural aspect of human life,” as opposed, for instance, to ritual that does but that also crosses boundaries between that which we habitually call “religion” in our culture and that which we habitually call the “secular.”
Peter Leithart sums up HERE the excellent book by acclaimed historian Peter Harrison sThe Territories of Science and Religion,
Once of the primary changes Harrison examines is from internal to external. Prior to the seventeenth century, both “religio” and “scientia” were virtues, not courses of study or institutional structures. According to Harrison, “for Aquinas religion (religio) is a virtue - not, incidentally, one of the preeminent theological virtues, but nonetheless an important moral virtue related to justice. He explains that in its primary sense religio refers to interior acts of devotion and prayer, and that this interior dimension is more important than any outward expressions of this virtue. Aquinas acknowledges that a range of outward behaviors are associated with religio - vows, tithes, offerings, and so on—but he regards these as secondary”.
Scientia was also a virtue or habit, but an intellectual one. In Harrison's summary, Thomas linked “science with the derivation of truths from those first principles, and wisdom with the grasp of the highest causes, including the first cause, God. To make progress in science, then, was not to add to a body of systematic knowledge about the world, but was to become more adept at drawing ‘scientific’ conclusions from general premises.
‘Science’ thus understood was a mental habit that was gradually acquired through the rehearsal of logical demonstrations. In Thomas’s words: ‘science can increase in itself by addition; thus when anyone learns several conclusions of geometry, the same specific habit of science increases in that man'”. On these premises, its’ all but nonsensical to claim that there is, or isn't, war between science and religion. Scientia and religio aren’t the sort of things between which there can be war.
Harrison discerns that a seemingly innocuous grammatical change signalled tectonic shifts. Calvin wrote of “Christian religion,” religio Christiana. English translators added a definite article that was not in the original Latin. According to Harrison, “the expression ‘the true religion’ places the primary focus on the beliefs themselves, and religion thus becomes primarily an existing thing in the world, rather than an interior disposition” as it was for Aquinas. During the seventeenth century, the definite article became much more common, with the unintended result of making “explicit belief and creedal knowledge” the content of religion .
If religion is a set of beliefs, then it can also be plural. And “true religion” no longer means genuine piety or devotion, but is the answer to the question “which religion corresponds to the facts?”