What has been will be again, what has been done will be done again; there is nothing new under the sun. This, in many ways, is the story of Christianity. From the times of Christ, till the present, Christians have had to confront Satan’s two swords—one physical and overt; the other spiritual and covert.

Consider the following excerpt on Christianity’s first three centuries, written by the Father of Church history, Eusebius of Caesarea (AD 263-339):

Like dazzling lights the churches were now shining all over the world, and to the limits of the human race faith in our Savior and Lord Jesus Christ was at its peak [after AD 313, following the rise of Constantine], when the demon who hates the good, sworn enemy of truth and inveterate foe of man’s salvation, turned all his weapons against the Church.

In earlier days he had attacked her with persecutions from without [for about 250 years, beginning with Emperor Nero, AD 63, and ending with Diocletian, AD 311]; but now that he was debarred from this, he resorted to unscrupulous impostors as instruments of spiritual corruption and ministers of destruction, and employed new tactics, contriving by every possible means that impostors and cheats, by cloaking themselves with the same name as our religion [meaning by pretending to be “Christians”], should at one and the same time bring to the abyss of destruction every believer they could entrap, and by their own actions and endeavors turn those ignorant of the Faith away from the path that leads to the message of salvation [4.7; emphasis added].

What is striking about this passage is how well the twofold attack it describes—external physical persecution (from pagan Roman emperors) and internal spiritual subversion (from Arianism and other heresies)—conforms to the rest of Christianity’s 2,000-year-old history and is especially applicable today.

It works as follows: Where possible, Satan possesses his minions to use a physical sword to persecute and slaughter Christians. Where not possible, he uses a spiritual sword to infiltrate and subvert Christianity so that, being themselves possessed, Christians choose death.

As seen, the most obvious and paradigmatic example of physical persecution is that referenced by Eusebius: pagan Rome’s savage persecution of Christians, which erupted from the time of the Apostles in the first century under Nero and sporadically continued till the rise of Constantine the Great, who outlawed religious persecution in the fourth century (specifically with the Edict of Milan, AD 313).

But the physical persecution of Christians continued far after Eusebius’s death in 339. The new persecutor—who, if not necessarily surpassing the quality of Rome’s persecution, has certainly far surpassed its quantity—was and remains Islam.

Writing around 1220—nearly a millennium after Eusebius’s times — James of Vitry, bishop of Acre, described Christianity as “besieged on all sides by enemies.” These enemies were, on the one hand, physical and obvious (Muslims) and on the other, spiritual and subversive (false Christians):

Saracens and pagans undermine the peace of Christendom, tyrants and evil Christians attack the liberty of the Church, and false brothers undermine love... For James and most Christians of the time, the answer was to fight fire with fire — by taking up the Two Swords of Christ:

Against the violence of the pagans and Saracens it [the Church] uses the physical sword [hence the Crusades]. Against tyrants and false brothers it uses a spiritual sword, which it also uses against heretics and schismatics…. Since the Church has two swords, which the Lord said “is enough” [Luke 22:38], one is to be exercised in a spiritual sense by the prelates, the other by princes and military Christians [emphasis added].

As foretold by Ecclesiastes, nothing has since changed. If the same double-pronged attack described by Eusebius was still on display nine centuries later, when James of Vitry was writing, today—a full eight centuries after James—it is worse than ever.