Once upon a time, the Greeks believed, Apollo, the god of prophecy, defeated the monstrous snake Python to take over Delphi and establish his own oracle. Housed in a cave, Apollo’s priestess, the Pythia, got high on laurel leaves and mysterious underground fumes. Inspired by the god, she then uttered confusing prophecies in perfect hexameter, inciting leaders to do things like found new cities, go to war (or not), and contract marriages (or not). No one knew what advice they would receive when they made the arduous days- or months-long trek to Delphi to consult the Pythia. Men who came to inquire about getting married, after all, are known to have been ordered to found a new colony halfway across the known world. And sometimes a prediction that going to war would bring a great empire to ruin might have been referring to the seeker’s own empire rather than his enemy’s. One never knew with the Pythia.

But Apollo, while master of Delphi, was not the only god in town. Modern-day tours of the site still attest to it as the centre of polytheistic worship. Every step of the way, as the modern visitor climbs the steep hill that forms the sacred precinct, one encounters another temple or treasury that once stored dedications to the gods. Lined up together, these buildings, each originally maintained by the city that sponsored its construction, form a who’s who of the Greek city-states.

In the middle of what seems like a forest of ruins, once just as overrun by ancient tourists as it is now by their modern flip-flop-wearing counterparts, still proudly stands the omphalos, the stone navel of the world. Ancient visitors were likely more respectful than modern graduate students, who pose happily with their belly buttons bared next to it. Guilty as charged. Some selfies are obligatory.

The Roman Empire at the time of early Christianity was a world filled with cult statues, blood sacrifices in temple precincts, and various other strange rites besides. All of these rites had to be performed just so, or else one faced the risk of disrupting the delicate pax deorum, the peace with the gods that was the foundation of Roman religion and culture. If the gods were happy with Rome, that peace would be maintained—and the Roman state would prosper, militarily and otherwise. If the gods were not happy, however, it was a sign that someone (or a group of someones) had disrupted the delicate peace. Immediate expiation would then be required, with religious rites ranging from the suovetaurilia (a package-deal sacrifice of a sow, a sheep, and a bull) to more drastic practices, like burying alive two Gauls and two Greeks in the cattle market (as the prophetic Sibylline books required after a couple of particularly dire military disasters).

The gold and the eye-popping paint colours that once adorned the ancient temples are long gone, but the remains of what once was are impressive reminders that the ancient world was filled to the brim with gods, and that people once truly believed in them. Divinities both major and minor were ever on hand (or not, depending on how they felt that day) to supervise all aspects of life—agriculture, childbirth, marriage, hunting, sailing, even sewage. The patron goddess of Rome’s magnificent sewer system, Venus Cloacina, did not have a temple at Delphi, but she had one located not far from Rome’s central sewer, the Cloaca Maxima. (Considering how much my family recently spent on updating the sewer mainline connecting our mid-twentieth-century home to the street, I can understand the need for a divinity that would ensure all plumbing worked swimmingly.)

To those of us who visit ancient religious sites today, the ruins testify to a religious environment vastly different from anything we experience in the modern world. All in all, if we had to describe Roman religion in a word, it might very well be “weird” or “strange.” Christianity, by contrast, seems woefully ordinary to us today, even to those who have not darkened the door of a church in years—or ever. But in the context of the Roman Empire, it was the Christians who were weird and Roman religion that was ordinary. Today’s perception of Christianity as normal is a problem for evangelism and for the integrity of our own faith, argues New Testament scholar and historian Nijay Gupta in his new book, Strange Religion: How the First Christians Were Weird, Dangerous, and Compelling. If church becomes too normal, Gupta observes, it becomes easy to live without it. It was precisely by being weird—albeit not deliberately or for the sake of being weird—that the early Christ followers stood out in a world filled with pagan gods. Their weirdness, while attracting persecution, also attracted converts. For contemporary Christians, this is a powerful reminder of saltiness (and weirdness) lost—which can yet be regained. This should begin for us, Gupta suggests, as it did for Romans, by recognizing the theological tenets of Christianity as weird, exceptional, unlike anything else out there—from the idea of genuine belief and conversion to the remarkable notion that not only are believers called to love each other but God loves them too.

Acknowledging the weirdness of Christianity in the pagan world is nothing new. But when we describe something as weird, the obvious question is, compared to what? This important question, too often ignored in discussions of early Christian weirdness, is at the core of this book.

While specialists in New Testament studies and early church history are aware of the pagan background to the early Christian world, Gupta’s target audience is non-specialist churchgoers, and they are likely never to have encountered this kind of systematic introduction to Roman religion before. Gupta’s valuable contribution to the church is to place Roman paganism side by side with the beliefs of the earliest Christians, thus setting in relief the latter’s historical distinctiveness. Strange Religion is thus equal parts tour of Greco-Roman pagan religion and introduction to early Christianity—what the earliest Christians believed, how they worshipped, how they lived, and how this all differed from their pagan neighbours.

The key difference that made the Christians weird, and which we take for granted, is the very idea of religious belief. We readily refer to Christianity as a “faith” in terms that emphasize the synonymity of religion and belief. We speak readily of interfaith dialogue, for instance, as a way of understanding the tenets of other religions. The Romans, however, did not see belief—or faith—as an essential component of their traditional religion. In fact, they were deeply suspicious of anyone who had beliefs. (That suspicion is what the Latin term superstitio described.) Sure, ancient pagans believed the gods existed, were all around, and were prone to get cranky if disrespected. But maintaining the pax deorum was all about doing the right things to avoid divine wrath falling on oneself (bad) or the city (worse) or the entire empire (worst of all). Greek and Roman mythology and lists of ill omens in the writings of Roman historians offer a handy and seemingly endless catalogue of everything that could go wrong if the gods were upset—plagues, earthquakes, rains of stones galore.

In addition to the idea of belief itself, what the early Christians believed—the basic precepts of Christianity that believers still hold today—was scandalously weird. Gupta notes, for instance, that the idea of believers loving each other was ludicrous to Roman outsiders. Of course, the same would be true for the idea that believers loved their God and, weirdest of all, that God loved them. It is no wonder that Roman pagan writers could accuse early Christians, who spoke of each other as brothers and sisters and emphasized their love for each other, as incestuous, pleasure-loving debauchers.

Christian worship, too, highlights the familiar-to-us features of Christianity that would have seemed shocking to Roman observers. Worship in a home rather than a temple? No statues used in worship? No priests—or even worse, all believers as priests, sharing in the priesthood of Jesus himself? All of these elements would have been perceived as transgressive and innovative, and the Roman world, Gupta reminds us, was deeply suspicious of innovation. Fidelity to tradition, especially as it pertained to Roman religion, was what maintained that fragile peace with the gods on which the welfare of the empire depended. In this light, the early Christians’ way of worship was not only weird but also dangerous. What if it upset the gods? A legitimate concern, in the Romans’ worldview, and one that in their minds justified persecution of Christians later on.

The idea of God’s proximity to his people was also appalling to the Romans. The possibility of a personal relationship with God, which we modern believers now consider so normal, would have terrified people familiar with stories about gods incinerating people by accident, turning them into wild beasts, or (best-case scenario) impregnating unsuspecting women while in the guise of a swan or a cascading shower of gold.

But no less terrifying than such scandalous proximity to God was the way the early Christians lived: they treated each other as equals. The Roman Empire was a deeply stratified society, one that equated that stratification with good and proper order. The Christians’ violation of this perceived natural order rightly seemed to observers to challenge the very existence of the empire.

Adding all these phenomena together, Gupta shows that many aspects of Christianity that we take for granted today are normal simply because we’ve had two thousand years to absorb them. Such is the case, for instance, with our thinking on equality and basic human rights for all people unconditionally. The early Christians, by contrast, stuck out like sore thumbs because of every aspect of their beliefs, worship practices, and lifestyle. They did not live out their faith perfectly, Gupta is quick to admit, but they were not afraid to be weird in an empire that persecuted any suspected rebellion.

The implications for the present readily emerge, as Gupta strongly hints. First, there is a valuable methodological takeaway from Gupta’s project. While churches are right to emphasize Bible reading and biblical literacy, historical literacy is quite low. Christians today, including lifelong churchgoers, are woefully uninformed about the history of the early church. Yet without the awareness of the historical context of early Christianity in the Greco-Roman world and its religious milieu, we do not understand the full picture of the early church. We fail to see what was—and should still be—special about Christianity. And so we fail to see the beauty hiding in the weirdness of the earliest believers—a beauty that attracted others to the faith in a way that no wild priestess in a fumes-filled cave ever could.

And second, there is the practical aspect to which this work of history gently calls us. Gupta asks poignant questions in this area: When Christianity appears to be “the opposite of weird,” when its sins and its priorities are indistinguishable from those of the culture it is meant to leaven, why do people even need the church? In other words, could trends such as the “Great Dechurching” and the rising number of “nones” stem from the church’s loss of its original weirdness? These questions urge us to consider the dangers of a shallow and conforming faith.

Being weird sounds great, but what does it mean for us specifically? It is tempting to look for concrete directives for recovering the weirdness of the early Christians, but Gupta stops short of giving us a precise checklist to follow. While at first glance this decision might seem frustrating, there is wisdom in encouraging the reader to reflect: What are the areas where each of us—in our local church context, in our neighbourhood, home, place of work—could bear witness and show sacrificial love to a suffering world just as Christians tried to do in the Roman Empire? Such work requires not universal imperatives but the virtues of prudence and fortitude to discern what the Holy Spirit is saying, and what is required of us in the cultures in which we find ourselves.

Gupta concludes, “The first Jesus followers were okay with being different, deviating from the status quo, following Jesus and his way wherever that went.” Christians today are called to do likewise.