This is an alternate universe where technology is just as advanced as IRL in all areas, with one key difference: Christianity never existed, and the most dominant world religion is Hellenism. Indeed, people worship Minerva, Libera and other such gods, mostly the Roman pantheon. In this world, history happened differently in a few aspects.

HISTORY

ANCIENT, MEDIEVAL AND EARLY MODERN HISTORY

• In this timeline, Constantine did not have a vision of the cross. Instead, he was guided to victory by dreams with the goddess Minerva. This made him highly devout to the goddess rather than to Christ, and gave an initial boost to the Roman religion and especially Minerva's cult in a way that set up the stage for the next political actions.
• Through a series of highly intelligent reforms, Constantine stabilized Rome, made it more meritocratic, stabilized the currency through a silver-backed standard and integrated many barbarians through a careful system of federalization. He also pushed for more subtle and less directly methods for containing this new Christian religion, understanding that if executions merely made martyrs, then other tactics were needed.
• Guided by more dreams of Minerva, he even ordered the Serapeum to be tightly protected forever and decentralized military logistics. He would become known in the future as "Augustus Minervae", the great emperor that saved Rome from what seemed like inevitable collapse and stabilized it for the long term.
• Over the next decades and centuries after Constantine's death, priestesses of Minerva gained new functions. The first of them were of librarians and something akin to copy monks, helping create copies of all the texts in the empire's great libraries and multiply them so scholars everywhere in the empire could access it.
• This increased accessibility effectively brought about the Renaissance over a thousand years earlier, stronger, and with nothing needing to be "reborn", just a continuation of the glorious imperial trajectory. The scientific method was developed over a thousand years earlier, industrialization occurred a thousand years earlier, and so on.
• Over time, social developments led to gradual religious reforms. Instead of needing a brutal rupture with the old order, though, changes like allowing women to study in Minerva's temples while young led to gradual reforms, turning these temples into something like schools for girls and young women, who mostly chose to go back to lay life at the end of it anyways.
• Women were liberated gradually rather than brutally, and slavery never reached quite the same level of brutality as racist chattel slavery from the colonization period: paradoxically, the Roman lack of a belief in "all men being equal before God" meant that they didn't have to see other groups as less than human to enslave them, which in turn led their slavery to remain only as inhumane as it was, and fizzle out more quickly once industrialization and capitalism pushed for less slaves and more wage workers.
• The Empire never quite developed the dehumanizing racism of the IRL timeline, though as overseas colonization took place, they certainly developed a sort of xenophobia towards the barbaric peoples of Africa and the Americas. To some degree, oppression of this kind persists to today, though almost entirely in indirect, covert manners like implicit biases, pay gaps, generational wealth, etc.
• Because of the non-dogmatic nature of Hellenism, which never even have any real orthodoxy or attachment to people having correct beliefs, there was no conflict with science. No Galileo being imprisoned for claiming Heliocentrism, no Protestant movement, nobody resisting the teaching of evolution in science classes. This also means there was little reason for science and the state to cleanly divorce from religion: to this day, the vast majority of people in the Western world are religiously Hellenic, even among the highly educated, scientists and whatnot. The lack of tension also makes for a much more reduced need of a radical materialist philosophy, and if science wants to make use of methodological naturalism, that's simply viewed as a quirk of the method for investigating nature, with those interested in metaphysics merely speaking of miracles as occasional rather than a repeatable occurrence controlled by humans, of divine providence moreso rather than constant supernatural direct operation in the world, and so on.
• In colonization and conquest, the religions of other peoples were never crushed, but merely assimilated, with influences being accepted where the Romans judged them reasonable, and much Interpretatio Romana taking place. Thus, the independent nations in America, while mostly Hellenic, still often express Aztec, Mayan, Incan or Haudenosaunee religiosity. Similarly, Yoruba is a popular religion in Africa.

MODERN AND RECENT HISTORY

• All of the world's pagan religions (and "pagan" in this setting just means "civilian" — a pagan religion is a civilized religion) have cross-pollinated greatly. Just about everyone believes in metempsychosis, or transmigration, in a way largely informed by cross-pollination with Hinduism and Buddhism during commerce with Asia that was established in the year 500 P.J (Post Caesar, after Julius Caesar's death). Just about everyone believes that one's next life and future fortune, while largely unknowable, is sure to be influenced by the mental impressions they create in themselves through every conscious decision made in this life and carried over from previous ones. Interpretatio Romana was and is applied widely, with Krishna being seen as Hercules, Durga as Minerva, Parvati as Venus, and so on.
• This dharmic cross-polination caused animal rights and environmental concerns to develop a bit earlier, meaning global warming was detected and started being dealt with much earlier. Global warming in this setting is still at merely 0.5°C above pre-industrial levels, cities are commonly filled with trees planted on sidewalks and everywhere nature is more well preserved than IRL. Big cities are never purely gray, but always have plants on every sidewalk of every block.
• "Scholasticism" existed in this world, but as a philosophical movement that lasted a few centuries after Constantine, with its known Quaestio Disputata format. It was eventually superseded by Modern philosophers like Immanuel Kant, Hegel, Husserl etc, which were largely similar to their IRL timeline equivalents, except for being Hellenic rather than Christian. With the sole exception of Husserl, who was Jewish in this timeline as well.
• The two World Wars did also happen in the previous century, though nazism did not exist: only fascist ideology was a thing, a revival of old imperialist values, splitting what was already the democratic Roman Confederacy into two great nations, the Roman Empire and the Roman Confederacy. The Confederacy won, and the entire territory of the Roman Empire at its peak today belongs to the Roman Confederacy. Fascism was not antisemitic or quite properly racist, though it was pro-slavery and did enslave some Jews and other groups for the decade it lasted.
• The knowledge preserved from the Serapeum allowed for the nuclear non-proliferation agreement to be way better enforced, meaning the Cold War was much less severe and there aren't nearly as many nukes laying around nowadays, nor can anyone make new ones.
• Communism in this world is an ideology associated not with "dialectical materialism", as Karl Marx in this timeline was an Absolute Idealist like Hegel — in fact, a Left-Hegelian — and one who worshiped Minerva, Justitia, Ceres and Nemesis. In fact, Nemesis is the goddess most often invoked by leftists, with billionaires being commonly accused of hubris that invites the providence of Nemesis in this life or the next. Communism is not even associated with Marx specifically, so much as "left-Hegelianism", with Hegelianism itself being respected by philosophers, though its political extremist variants (left-Hegelianism associated with communism, and right-Hegelianism associated with fascism) are derided by most.
• Portugal and Spain do not exist, nor do the languages of Portuguese and Spanish. Nearly the whole European continent speaks Latin, and so do most peoples in the Americas. Programming languages with the same names as IRL exist, though code is written in Latin rather than English, a language which does not exist in this setting.
• On a theological level, the most popular theologies ended up being descendants of Neoplatonism. While much has shifted and asceticism is notably impopular in this capitalist era, the basic idea that the gods are aspects or personified facets of one divine essence ("The One") is nonetheless a standard view ("Polymorphic Monotheism") of most of the more scholarly individuals, interested in theology and the philosophy of religion.

THE WORLD TODAY

• Due to the headstart permitted by not losing the Serapeum, the year is 1025 P.C, with P.C meaning "Post Caesar", or after Julius Caesar's death. The level of science, technology and general human knowledge is the exact same as 2025 A.D from the IRL timeline. No sci-fi elements. Only real difference is that global warming is less severe and cities are greener.
• Hellenism is the most popular religion worldwide. Christianity is a mere footnote in history books, lasting a few centuries of a wacky and chaotic period in the empire's history before being re-assimilated into Roman hegemony, and generally seen as just part of the social instability of late antiquity. Judaism is still around, if largely irrelevant to politics: not persecuted though somewhat oppressed in the same vague largely socioeconomic and implicit way many descendants of barbarians are, especially non-Hellenic ones. They don't have any memory of a Holocaust, though, and Israel is a long-forgotten dream. Syria Palestina is a province of the Roman Confederacy, though.
• The week days are all tied to different gods, which tend to receive offerings more often on their respective days. Monday is dedicated to Diana and Ceres; Tuesday is dedicated to Mars and Minerva; Wednesday is dedicated to Mercury and Vulcan; Thursday is dedicated to Jupiter and Juno; Friday is dedicated to Bacchus/Liber and Venus; Saturday is dedicated to Vesta, Pluto, Proserpina and Saturn; and Sunday is dedicated to Apollo, Sol, Neptune and Salacia. Because weekends are dedicated to more gods, they are rest days and most people go to at least one temple at least one day out of the weekend.
• Nearly every major school or university campus has statues of Minerva, whom those with intellectual jobs are commonly devout to, and struggling students will often make offerings to her. During the last week of the month of July, in the Panathenaea — a festival dedicated to Minerva — it's common for many to spend all night studying or learning something, their mental efforts themselves an offering to the goddess.
• Prostitution is generally legal, with many priestesses of the goddess Venus or the god Bacchus being also prostitutes on the side. While women being promiscuous is frowned upon, with slut-shaming about as popular as IRL, even the most sexist of men will hold his tongue and not dare speak ill of women whose prostitution is protected by and dedicated to the gods, even if it's enjoyed by men in the exact same way. Throughout the year, there are four holidays dedicated to Bacchus (one of them the week-long Liberalia Magna festival form March 9th to 16th) and the entire month of April is dedicated to Venus, and prostitutes make bank during these times. Slut-shaming is also itself shamed during two of them, with the exception of cheating: women who are not taken are allowed and even to an extent expected to act promiscuous during the Liberalia Magna and the Floralia, and provided they use contraceptives and protection, promiscuity whether male or female is protected by the gods during these two week-long festivals.
• In general, sex is something that can be sacred, profane, or banal depending entirely on its intention and context. Loving couples may offer their sexual acts to Venus, prostitutes to Bacchus, and seek to gain blessings and protection in that way. Views on sex do vary: the more conservative frown on promiscuity at all times except during the major festivals of Bacchus and Venus, whereas the more progressives will be generally tolerant of promiscuity. However, all sharply distinguish between consensual promiscuity and the betrayal of others: cheating or violating sacred commitments is always gravely wrong.
• Casual, omnipresent piety is normal: almost everyone has a favorite deity (or a small cluster) and so do just about all places have an altar for a patron deity. Nearly every meal begins with a tiny offering of food into a flame, even if it's just a candle or a stove burner briefly dedicated to a deity: it's standard etiquette to push a tiny bit of one's food (a few grams) into the fire before one starts eating. People will often refer to "your patron" or "the gods you serve" when talking about life choices, exams, relationships, or health, and casually suggest deities to make offerings to given situations.
• Due to cross-pollination with Eastern religiosity, beliefs in "fate" have become more flexible over the centuries, and mixed with karma. Karma is not viewed as simplistic "good deed → reward", but rather understood as every conscious choice one makes becoming imprinted in their lives and shaping what they gradually become over the course of one life or the ones after (metempsychosis/transmigration is the standard afterlife belief, with people often self-deprecatingly joking "I must have stolen food from an altar in a past life" or similar things when something bad happens to them). Beliefs of karma are neither framed as victim-blaming, nor denial: suffering is partly inherited karmic weather, partly social structure, and partly opening for divine play (lila), thus active response, ritual, and ethical action instead of resignation are encouraged.
• Gods from other cultures are commonly viewed through the lens of "interpretatio": everyone is comfortable viewing the Egyptian goddess Neith as "that's the Egyptian word for Minerva" and just treating the names of gods from other religions as another language's translation for the names of gods in one's own language. When non-Western traditions are mentioned, structural resonance is looked for, rather than simple "true vs false". Pagan/civilian religions are all understood as partial views of the same spiritual reality.
• Most people are critical but loyal to the Roman Confederacy: this civilization which is the heir of the Roman Empire, turned democratic (Roman Empire → Roman Confederacy) during the Industrial Revolution, is the natural framework of civilized life, but everyone criticizes corruption where it exists and views injustice as a betrayal of Rome's sacred mission. Popular reforms are often viewed as offerings to Jupiter, Juno, Minerva and Justitia.
• The whole political spectrum exists, affecting views on sexuality (levels of tolerance of promiscuity), attitudes towards barbarian peoples and their descendants, economic views and so on. There is no side that is more or less religious, though more conservative individuals may speak more of Jupiter's order and more radically progressive individuals may speak more about Justitia and Nemesis' karmic retribution. Many people also talk about "not angering Ceres" when discussing pollution, bad urban planning, and ecological causes.
• Due to Friday being dedicated to Venus, people are commonly more playful and socio-sexual during that day, with "couples making love in friday nights" being a common trope that's also a part of life. Similarly, people often talk about being still sleepy from the weekend during Monday (the day of Diana and Ceres), but "locking in" to work or study harder on the Tuesday (the day of Mars and Minerva).