This article is Part 2 in a series. Be sure to start with Part 1!
Author's Note: What follows is a personal hypothesis. While I am a devoted member of the Orthodox Church, this work does not reflect the official position of the Orthodox Church nor does it speak on behalf of it.
Rather, it represents my own synthesis and reflection on the long historical arc of spiritual warfare I believe has been waged against God, Christ, and His Church from the moment of the Incarnation until now. Ideas and concepts articulated within this article come from my own understanding of early church and reformation history, orthodox and roman catholic podcasts and some evangelical sources. (Where these types of views tend to be the most prevalent.)
Demonic Strategy for a Counterattack
If Christ’s arrival exposed the enemy and bound the strong man (the Devil), what’s the enemy’s first move in the counterattack? Because he will counterattack. He’s not going to just sit back and let his kingdom be destroyed and usurped.
When the demons realized that they wouldn’t be able to outcompete the Lord’s gospel, they embarked on a two-pronged strategy: resist/suppress and distort/corrupt. They began by using their traditional “kingdoms”, the state-sponsored pagan religions, to try to resist Christ’s kingdom. But from the very beginning, the father of all lies embarked on a strategy of attempting to corrupt the Gospel from within.
The Devil doesn’t necessarily begin with an open-your-in-your-face confrontation; that’s too bold and risks galvanizing and building resilience. When he does this, he uses those he has deceived to do his dirty work. But first, he needs to weaken and distort to the point where things can more easily fall into his grasp. And we see this when we look at the rise of Islam and the Reformation wars. In my opinion, he doesn’t want to make people aware of his moves, so he’s going to try to play the game from the shadows, playing puppet master by pulling the strings, but never directly being visible on stage.
The Demons’ Greatest PR Win: Getting Us to Laugh at Them
C.S. Lewis nailed it in The Screwtape Letters:
“Our policy, for the moment, is to conceal ourselves… If people don’t believe in devils, we lose the pleasing results of direct terrorism and we make magicians. But if people don’t believe in us at all, we have already won.”
The ancient world feared the gods. Ours just memes them. Some might say that’s enlightened progress. I say, that’s vulnerability caused by spiritual blindness. The less seriously we take the idea of spiritual deception and a war with unseen demonic powers, the more susceptible we are to them.
Instead of being overly creative, the father of lies uses a tactic that’s worked since Eden: imitate the truth closely enough to fool the undiscerning, then twist the results to his ends. The devil never produces something that is 100% a lie; that’s too easy for people to detect as false. Instead, he combines lies and falsehoods to mislead people while keeping them unaware.
I have often said in the past, when speaking to my children, that the most powerful lie is the one that contains the most truth. It’s worth remembering that counterfeiting isn’t about creating something entirely new. It’s about taking what’s real, then distorting it just enough to corrupt the source. That way, the victim thinks they’re still in the light while they slowly acclimate to the dark.
I’ve also heard it put this way. You can take the most wonderful and most valuable bottle of wine in the world, but add a couple of drops of poison to the wine, and it will still kill you.
Counterfeits Work Better Than Force
Open persecution can strengthen the faithful — history proves it. Counterfeits, however, lull them to sleep. It’s far easier to keep someone in bondage if they believe they’re already free.
In the centuries before and after Christ, this took the form of:
State-backed paganism — the empire as a religious project, with loyalty to the gods equated to loyalty to the state.
Syncretism and Heresy — absorbing Christian language into pagan frameworks, producing “Christianized” heresies that carried just enough truth to pass muster.
Twisted asceticism — counterfeit “holiness” that fed pride rather than humility.
The Gods of the Nations Were Real — Just Not Who or What They Claimed to Be
Today, when we learn about ancient Rome in school, paganism is often presented through the eyes of mythology. This is a distortion. People in ancient times were just as intelligent as we are today. Nobody was going to worship simplistic myths, particularly when effort and sacrifice are required to do so. The idea that it was just mass delusion on the part of the average person, coincidence and false attribution, massive confirmation bias, and superstition is too simplistic and frankly arrogant an explanation. These false “Gods” did produce “works” and “miracles” of their own, often enough to engender belief. There were things in paganism that were so striking that the early patristic Fathers themselves took them seriously as real manifestations of spiritual power (albeit demonic). The ancient world was full of claims of wonders, and many of them were too consistent and too public to be dismissed as mere rumor. The Fathers, Roman historians, and even skeptical philosophers acknowledged them. Here are some examples:
Delphi (Apollo’s Oracle): The most famous pagan oracle was consulted by kings, generals, and statesmen. Herodotus, Plutarch, and others record accurate, specific predictions. Example: Croesus of Lydia was told that if he attacked Persia, he would “destroy a great empire,” which came true (his own). Ambiguous? Yes. But there were times when oracles gave strikingly accurate answers (Plutarch, a priest at Delphi, confirmed this even centuries later).
Patristic witness: St. Justin Martyr and St. Athanasius both point to oracles ceasing with the coming of Christ as proof they were demonic.
Asclepius (god of healing): Temples of Asclepius (Asclepieia) across Greece and Asia Minor were pilgrimage centers. Archaeologists have recovered inscriptions where healed individuals recorded their cures: lameness restored, blindness healed, even resurrections. People slept in the temple (incubation) and reported visions of the god or snakes (his symbol) healing them.
Christian view: Not psychosomatic alone — demons sometimes “gave” diseases or afflictions and then “healed” them through pagan rites, to win devotion.
Pagan gods were often said to appear in visible form.
Alexander the Great claimed Athena guided him at Troy, and Zeus-Ammon at Siwa confirmed his divine status.
Roman generals (like Sulla and Augustus) claimed visions of gods encouraging them before battle.
Pausanias and Livy record apparitions of Castor and Pollux fighting alongside Romans at the Battle of Lake Regillus (496 BC).
Orthodox perspective: demons can appear as angels of light (2 Cor 11:14). The fact that “gods” manifested visibly in pagan contexts is evidence of demonic mimicry rather than imagination alone.
Ecstatic Possession:
In many cults (Dionysus, Cybele), worshippers experienced frenzied states, glossolalia-like speech, superhuman strength, or insensitivity to pain.
Even Plutarch and Cicero describe people seized with powers not explainable by ordinary psychology.
These resembled demonic possession in the Gospels — and Christians interpreted them exactly that way.
Pagan temples often had “miracles” associated with them:
Statues speaking or moving (Livy records such prodigies in Rome).
Miraculous manifestations during sacrifices.
At Dodona (oracle of Zeus), responses were given through rustling of sacred oaks and bronze cauldrons sounding without human touch.
The Christian claim was not that all of these were fakes — but that demons animated idols, statues, or natural forces to awe worshippers.
Patristic Testimony
We’ve inherited a modern, sanitized idea that the pagan “gods” of the ancient world were like superhero Marvel characters — colorful myths, campfire stories, and cultural artifacts. However, that’s not how the apostles or the early church Fathers understood them. These phenomena were effective because they really happened, not because ancient people were gullible.
That’s why the Fathers spoke of them with deadly seriousness. The Church Fathers confirm this again and again. St. Justin Martyr, St. Irenaeus, and St. Athanasius all insist that pagan worship was not neutral folklore but enslavement. St. Athanasius writes in On the Incarnation that before Christ, “idolatry and the fraud of demons filled the world.”
Paganism was much more than a pantheon of gods based on wonders and myths; it was a system of spiritual management, control, and enslavement. The “gods” were real, but they were not divine, nor were they holy. They were fallen spirits, enthroned by human fear, feeding on worship.
“All the gods of the nations are demons.” (Psalm 95:5 LXX)
“The things which the Gentiles sacrifice, they sacrifice to demons and not to God.” (1 Cor 10:20)
The Septuagint calls this out and doesn’t pull any punches: “All the gods of the nations are demons.” (Psalm 95:5 LXX)
Paul also echoes this directly: “The things which the Gentiles sacrifice they sacrifice to demons and not to God.” (1 Cor 10:20)
The Patristic Fathers didn’t soften this.
St. Justin Martyr says demons, foreseeing baptism, “instigated those who enter their temples to sprinkle themselves also” — a demonic imitation of Christian washing.
St. Irenaeus describes the devil “setting himself up as God” to be worshipped by the nations.
St. Athanasius, in On the Incarnation, says Christ’s coming “exposed the fraud of the demons” and broke their hold over idolaters.
St. Cyril of Jerusalem told catechumens bluntly that the pagan mysteries were “full of imposture” and driven by evil spirits.
St. Athanasius (On the Incarnation): notes that before Christ, pagan gods and demons worked signs to hold men in fear, but after the Cross their power collapsed.
St. Justin Martyr (1st Apology, ch. 54): explicitly says demons imitated Christian rites and sometimes worked marvels to deceive people.
St. Augustine (City of God, Book VIII): catalogs many pagan miracles, admitting their reality but attributing them to demons, not gods.
Origen (Against Celsus): acknowledges demons gave oracles and signs, but insists Christ’s miracles were categorically different — oriented to love, truth, and transformation.
The Church Fathers consistently teach that:
Demons can afflict bodies and minds, only to then appear as healers.
Demons can manipulate matter (illusions, voices, apparitions).
Demons can foretell events — not as God does, but by observing causes invisible to us (like angels seeing far in advance the consequences of human actions).
The Death Throws of Roman Paganism
As we’ve seen, the pagan world was not a void waiting for truth — it was occupied territory, thick with ritual counterfeits designed to mimic the holy while enslaving the soul. And even with the unstoppable advent of Christ’s kingdom, Satan was not about to give up his fraudulent edifice so easily. Paganism would remain for quite some time, even after Constantine legalized Christiantiy, to challenge the growth of God’s kingdom, even to the point of being the lightning rod to which Roman emperors like Nero, Trajan, Decius, Diocletian and Julian the Apostate rallied to attempt to halt and overturn the spread of Christianity. Many think that the persecutions ended with Constantine the Great, but this is not the case. Below is a brief history of the final struggles against the corruption of the true faith.
Julian the Apostate (361–363 AD)
Julian was raised a Christian but rejected the faith, converting back to Neoplatonic paganism.
Constantine the Great had 3 sons: Constantine II, who ruled in the west (died in battle); Constans, who ruled the central provinces (was assassinated); and Constantius II, who ruled the east, eventually becoming the sole emperor. He was strongly pro-Arian.
This was the last major attempt to restore paganism as the empire’s religion.
Julian rebuilt pagan temples, reinstated sacrifices, and banned Christians from teaching classical literature (to cut them off from culture). He tried to present paganism as morally and intellectually superior.
He called Christ a “Galilean” and mocked the Church’s unity and power.
His reign was short, and after his death, support for true orthodox Christianity varied. His successor, Jovian (363–364), restored Christianity and reversed the pagan reforms. He was succeeded by two brothers who split the empire, one Valentinian I (364–375), a Christian in the west. In the east, his brother, Valens (364–378), an Arian Christian who opposed orthodoxy, was killed in battle with the Goths 14 years into his reign.
Gratian (367–383) inherited power in the West. He removed state subsidies for pagan cults, beginning their demise in the Roman Empire. Once those subsidies disappeared, paganism lost its institutional foundation. It had little ability to function without state funds because it wasn’t structured like the Church (with voluntary tithes, networks of bishops, etc.). Gratian also refused the title Pontifix Maximus, a pagan title. This title referred to the pagan high priest of the Roman state religion - a political and religious office responsible for maintaining peace with the god through correct rituals. Pontifex means bridge builder - one who mediates between God and men. Gratian dropped the title; however, eventually the bishop of Rome took it up, which is why he is referred to as the Pontiff today.
Theodosius I “the Great” (379–395) came to power in the East. He helped finally put an end to the Arian heresy and made Orthodoxy the official state religion of the Roman Empire.
Theodosius I delivered the final death blow to Roman Paganism:
Edict of Thessalonica (380): Made Nicene Christianity the official religion of the empire.
Outlawed public pagan sacrifices and closed many temples.
By the end of his reign, paganism was effectively dismantled as a public religion.
Hallmarks of a Perfect Counterfeit
From the record of Scripture, the Fathers, and even common sense, we can see a recurring method in how the demonic counterfeits the holy.
1. Cloak it in Familiarity
Use language, ritual, and imagery that echo the truth. Paganism borrowed sacrifice, priesthood, processions, feasts, incense — all things God gave Israel — but redirected them to false gods.
2. Appeal to the Passions
Promise fertility, victory, prosperity, indulgence in sensual passions and secret knowledge that gives people an advantage over others. Sacrifices become transactional bribes to keep the gods happy. Rites become occasions for indulgence rather than purification.
3. Invert the Image
What is holy becomes profane, and what is shameful is honored. Child sacrifice becomes a sacred duty. Sexual immorality becomes part of pagan temple worship. The soul is re-formed in the image of what it adores — which is why the Psalmist says of idolaters: “Those who make them will become like them.” (Ps 115:8)
This is also why St. John, says that they will call Good Evil and Evil Good. He recognized a pattern in how the demons operate.
Pagan Counterfeits
To understand the strategy, we need to remember how these cults actually functioned:
Oracles and Divination. Pagan temples often functioned as centers of “revelation.” Priests or priestesses would deliver answers from Apollo, Zeus, or other gods — often after trances or rituals. The Fathers saw this as demons imitating prophecy, giving just enough truth to deceive, while binding people to false spirits.
Sacrificial Systems. Animal sacrifices, food offerings, and libations were made daily. But some cults demanded human sacrifice (notably to Moloch in the Levant, or in certain Celtic practices). The demonic signature here is unmistakable: inversion of the true Sacrifice of Christ, demanding death rather than giving life.
Temple Prostitution. In Corinth, the temple of Aphrodite famously employed hundreds of prostitutes. Sexual indulgence was framed as communion with the goddess. Compare this with Christian chastity and the Eucharist — one feeds the passions, the other purifies them.
Mystery Religions. Cults like those of Mithras and Eleusis had initiation rites involving blood, secret oaths, and ritual meals. St. Justin Martyr noted that demons created these specifically to mimic Christian baptism and Eucharist, so that when the Gospel came, people would dismiss it as “just another mystery.”
In short, paganism used religion’s natural structures (ritual, sacrifice, priesthood, mystery, ecstasy) but distorted them. This is precisely how counterfeits work: close enough to the truth to be mistaken for it, but bent just enough to enslave.
It’s not a coincidence that paganism, heresy, and modern ideologies “look similar.” It is deliberate. They all stem from the same strategy: counterfeit the holy.
Pagan sacrifices → counterfeit of Christ’s Sacrifice.
Pagan initiation rites → counterfeit of baptism and Eucharist.
Gnosticism → counterfeit of illumination and theosis.
Montanism → counterfeit of prophecy and the Spirit.
Prosperity gospel → counterfeit of Christian blessing and eternal divine inheritance.
Social media oracles → counterfeit of prophetic voice.
This is why the early church Fathers insisted that: worship is never neutral. You will either worship the true God, or counterfeits will form you. And if theosis is the process of becoming like Christ, then counterfeit worship is its dark mirror — deformation into the image of demons. Another reason why the early church fought so hard against what they saw as heresy in any form.
The First Christian Counterfeits: Early Heresies
When the demons realized that they wouldn’t be able to outcompete the Lord’s gospel, they embarked on a two-fold strategy: slow its growth and distort it. We’ve seen above how they used their traditional “kingdoms”, the pagan religions, to try to resist Christ’s kingdom. Below, we will briefly explore their efforts at corrupting the Gospel from within.
If you can’t beat them, join them.
(i.e. when opposition fails, co-opt your rivals’ practices.)
Unable to stop the spread of the Gospel, demons have been attempting to corrupt it from within (almost since day one) by planting distortions that mimicked the language of Christianity while poisoning its essence. These heresies didn’t arise in a vacuum. They are strategic counterattacks, designed to fracture the young Church by mimicking the true Gospel while subverting its core.
The New Testament itself is already pushing back against distortions. Below is a timeline of the earliest heresies:
1st Century (during the time of the Apostles)
Judaizers (40s–60s AD)
Insisted Gentile Christians must keep the Mosaic Law (circumcision, kosher, etc.).
Opposed by St. Paul in Galatians, Acts 15 (Council of Jerusalem).
Proto-Gnosticism (50s–90s AD)
Gnosticism claimed that salvation came through secret knowledge (gnosis) available only to the elite. They taught that Christ was a revealer of hidden truths, not the Savior who took on flesh and died. This was a demonic parody of true illumination and theosis. Instead of communion with God, it offered pride and elitism.
St. John warns against those who “do not confess Jesus Christ has come in the flesh” (1 John 4:2–3).
The Book of Colossians also pushes back against early “philosophy, empty deceit…worship of angels” (Col 2:8,18).
Docetism (late 1st century)
Docetism. Taught that Christ only “seemed” (Greek dokein) to have a body, denying the Incarnation. This was a direct assault on the mystery of God made man. If Christ did not truly take on flesh, then humanity was not truly healed. Demons push this to strip the Cross of its saving power.
Opposed in 1 John and by Ignatius of Antioch (c. 110 AD).
Nicolaitans (late 1st century)
Mentioned in Revelation (2:6, 2:15). Believed to have promoted sexual immorality and eating food sacrificed to idols.
2nd Century (100s AD)
Full Gnosticism (100s AD)
Became a system of competing sects (Valentinians, Sethians, Basilideans).
Claimed salvation by hidden knowledge, rejected the Creator God as evil/demiurge, and denied the true Incarnation of Christ.
Refuted by Irenaeus, Against Heresies (c. 180 AD).
Marcionism (c. 140 AD)
Marcionism. Claimed the God of the Old Testament was evil and that Christ came from a different, higher deity. This was a demonic wedge meant to sever Christianity from its Jewish roots and the testimony of Scripture.
Rejected the OT entirely, created his own “canon” of edited versions of Luke + Paul’s letters.
One of the first major heresies that forced the Church to clarify the canon.
Montanism (c. 156–200 AD)
Founded by Montanus in Phrygia. Claimed to bring new prophecy, emphasizing ecstatic visions and extreme asceticism.
Began as a charismatic movement emphasizing prophecy and asceticism, but quickly veered into claiming a “new revelation” beyond Christ and the apostles. Again, a demonic counterfeit: mimic the Spirit, but twist it toward pride, extremism, and schism.
Presented itself as the “new age” of the Spirit beyond Christ and the apostles.
Opposed by bishops and synods across Asia Minor and Rome.
3rd Century (200s AD)
Sabellianism / Modalism (early 200s)
Denied the Trinity by claiming Father, Son, and Spirit were just “modes” of one God, not distinct Persons.
Opposed by Tertullian and later councils.
Novatianism (mid-200s)
Schism, not doctrinal heresy: refused readmission of Christians who had lapsed under persecution.
Shows how rigorism and legalistic thinking could fracture the Church.
4th Century (300s AD)
Arianism (c. 318 onward)
Taught by Arius (Alexandria). Denied the full divinity of Christ, claiming the Son was a created being.
Nearly conquered the empire until the Council of Nicaea (325) condemned it.
Perhaps the most dangerous heresy in Church history.
As you read through these early heresies, do you notice any threads of continuity? Themes that you perhaps see recur through time? If you think about it, you’ll see some of these same things reappearing in the modern era.
They are the “trial balloons” of the enemy, setting the stage for the larger crises of heresy and persecution in the next centuries, which we’ll explore in Part III.
Modern Counterfeits: Same Strategy, Different Branding
The method hasn’t changed — only the packaging. Today, the counterfeits are often secular, like the material rationalists, new atheists or those who pass of false religion under the banner of being spiritual but not religious. Below are some other directions that counterfeits take today.
Wellness as salvation — the language of wholeness without repentance.
Prosperity gospels — baptized greed wrapped in the veneer of the Bible.
Self-made spirituality — rituals curated from a buffet of traditions, with the self firmly enthroned as the pope of one’s own religion.
Activism as identity — causes elevated to the level of religion, with heretics to be shamed and saints to be canonized on social media.
Digital idols — algorithmic feeds discipling hearts more effectively than most pulpits.
Worship of Self - individualism taken to its ultimate conclusion.
These aren’t harmless lifestyle choices. They are worship systems, often unconsciously adopted, shaping their adherents in the image of something other than Christ.
Baptism as the Original Counterfeit Breaker
The Orthodox rite of baptism, from the earliest days, began with exorcism and renunciation. It still does. The first thing we do is face west — the direction of darkness — and spit at Satan. This is not mere symbolism — it is a tearing up of the devil’s contracts and any hold he may have on us.
That physical, deliberate movement is intended to break with all counterfeits. It says:
I reject false gods and their promises.
I renounce the passions they feed.
I refuse their image and claim the image of God restored in Christ.
The Warning for Us
Today, we may think that we’re too sophisticated for idols carved in wood or stone, or that the devil is too sophisticated to need them. The counterfeits of our age wear jeans, carry cell phones, have large social media followings, offer personal growth and self-help classes, and talk about “living your truth” or being "spiritual but not religious.” They don’t look demonic — they look normal. And that’s the point.
The Fathers would recognize them instantly, not because they had Instagram, but because they knew the smell of a counterfeit. And they would tell us what they told their own flocks: Do not think you can serve two masters. Your worship will shape you.
The Modern Counterfeits
Counterfeits didn’t vanish with the fall of pagan temples. They just updated their branding. The logic is the same: imitate, redirect, attack, and enslave.
Wellness Spirituality. Promises wholeness, peace, even “healing,” but without repentance, sacraments, or Christ. It mimics salvation while keeping the self enthroned.
Prosperity Gospel. Takes biblical language about blessing and twists it into baptized greed. These counterfeits also overemphasize the biblical pattern of righteousness versus wickedness, placing emphasis on "principles" that suggest people prosper when they are righteous, and God punishes wickedness by allowing suffering, misery, and poverty. Instead of the Cross, it offers cash. This is not just bad preaching; it is a systematic counterfeit of sacrifice, turning God into a vending machine.
Activism as Religion. Secular ideological movements (left or right) often mimic the structure of religion: creeds, saints, heretics, rituals, and even inquisitions. They offer belonging and moral fervor — but without Christ, they become counterfeits that enslave, divide, and spread animosity rather than liberate.
Digital Idols. Social media algorithms have become the new oracles, feeding curated revelations to disciples. They shape desires and fears more effectively than most priests. In patristic terms, this is the demonic art of distraction refined into an industry.
The Self as God. This is simply the serpent’s old whisper in Eden — “You shall be like God” — repackaged for a culture of radical individualism. Ancient pagans carved idols of stone, and modern pagans carve idols of the Self, demanding worship in the liturgy of identity politics. St. Augustine would call this the “curved-inward self” (homo incurvatus in se), where love that should be directed toward God and neighbor collapses into self-love, self-will, and self-definition.
The demonic counterfeit is not subtle: it mimics the confession owed to Christ and redirects it inward. What was once the Church’s confession to Christ — Philippians 2:10 “At the name of Jesus every knee should bow, in heaven and on earth and under the earth, and every tongue confess that Jesus Christ is Lord.” is now demanded of society for the sovereign Self, the modern counterfeit flips it: “At the name of my chosen identity, every knee should bow, and every tongue confess that I am Lord.” This is nothing less than a blasphemous inversion. Identity paganism has also created a pseudo-religious cult framework for itself:
Public confession of the self (“This is who I am”). (like a kind of creed.)
Public affirmation (“Say the words or you are a blasphemer.”) i.e., speak these pronouns, or go to jail for hate speech.
Sacred taboos (forbidden speech, e.g., “dead naming”).
Ritual punishments (excommunication by being cancelled).
St. Maximus the Confessor warns that the passions (desire, anger, pride) enslave us when the self makes itself the center.
St. John Chrysostom calls pride “the queen of sins” because it makes man think himself God.
St. Anthony the Great said, “The time is coming when people will go mad, and when they see someone who is not mad, they will attack him, saying: ‘You are mad; you are not like us.’” This fits chillingly well with the madness of identity absolutism today.
Looking at this type of paganism through this lens is, admittedly, quite dangerous. I think that we all need to be careful not to demonize entire groups of people by adopting this kind of perspective. We need to remember that the Devil and his demons have a hold on all of us in one way or another; sin is sin. Just because we have different sins and struggles doesn't make me better or worse than anyone else. As far as I know, in Orthodoxy, we don't have a hierarchy of sins (venal, mortal, etc.) It’s just all sin, and as disciples of Christ, we are forbidden to pronounce judgment and should remember to treat all individuals with love and respect. We all need a hospital, and we all need healing, regardless of the nature of those wounds.
The Fathers would see this clearly: the same passions are being fed, and the same worship patterns are being mimicked. The devil no longer needs altars of stone. He has screens and the internet.
Next: The Mask Slips
When Christ is on your side and you've been bound, sometimes the old demonic counterfeits aren’t enough. Sometimes, the enemy feels the need to transition from subtle imitation to an all-out open attack. That’s when swords are drawn, and heresies arise through the corruption of men’s hearts to lead the faithful away. Or have them driven into courts, prisons, and arenas.
That’s where we go in Part III: Swords from Without, Cracks from Within — the era of open persecution and creeping heresy, and why both are part of the same war.
Further Reading
Scripture
Psalm 95:5 (LXX), 1 Corinthians 10:20–22
Acts 17:16–34 (Paul confronts the idols of Athens)
Colossians 2:8, 2:14–15 (Christ disarms the powers)
1 John 4:1–3 (testing spirits)
Patristic Sources
Justin Martyr, First Apology (esp. ch. 62 on demonic imitation)
Irenaeus, Against Heresies (refutation of Gnosticism, Docetism, Marcionism)
Athanasius, On the Incarnation (idolatry as fraud of demons)
Cyril of Jerusalem, Catechetical Lectures (on exorcisms and renunciation of Satan)
Tertullian, On Prescription Against Heretics (heresies as demonic distortions)
Modern Historical/Scholarly Works
Jaroslav Pelikan, The Christian Tradition, Vol. 1 (on heresies and the early Church)
Andrew Louth, The Origins of the Christian Mystical Tradition (on Gnosticism and pagan backgrounds)
Everett Ferguson, Backgrounds of Early Christianity (on pagan cults and mystery religions)
C.S. Lewis, The Screwtape Letters (popular but insightful on demonic strategies)
David Bentley Hart, Atheist Delusions (on how Christianity dismantled the pagan religious system)