The Crusades and the Inquisition show what Christianity does with power — holy war, torture, and burning people alive for wrong belief. A religion capable of that cannot be a religion of love.

Why people find it persuasive

These are among the most vivid and well-known episodes of Christian history, involving real violence justified in explicitly religious terms by popes and church courts.

Important distinctions

• • Historical fact of violence committed by Christians and church institutions vs. whether that violence follows from, or contradicts, the New Testament's own teaching.
• • The Crusades' specific medieval geopolitical context (a defensive-turned-offensive response to centuries of Islamic conquest of formerly Christian territory) vs. the popular image of unprovoked aggression.
• • The scale and nature of the Inquisitions as actually documented by historians vs. the popular 'Black Legend' image.
• • Institutional and political violence carried out in Christ's name vs. Christ's own explicit teaching and example.

Christian response

• • The Crusades (beginning 1095) emerged in the context of nearly four centuries of Islamic conquest that had already taken the once-Christian-majority regions of the Levant, North Africa, and Spain, and were launched partly in response to a direct appeal from the Byzantine Emperor Alexios I for military help against Seljuk advances — this context does not justify the atrocities that followed (including the horrific 1204 sack of Christian Constantinople itself by the Fourth Crusade, condemned by Pope Innocent III at the time), but it complicates the 'unprovoked religious aggression' framing.
• • Modern historical scholarship (Henry Kamen's and others' archival work on the Spanish Inquisition) has substantially revised the popular 'Black Legend' image: the Spanish Inquisition's documented execution total across its multi-century existence is now estimated by historians at roughly 3,000-5,000, far below older popular claims of millions, though even one execution for heresy is a moral atrocity requiring no minimization to be condemned.
• • Jesus' own explicit teaching and example run directly counter to religious violence: he rebukes Peter for drawing a sword in his defense ('all who take the sword will perish by the sword,' Matthew 26:52), instructs turning the other cheek and loving enemies (Matthew 5:38-44), and submits to unjust execution without resistance, refusing to call down legions of angels (Matthew 26:53) — the Crusades and Inquisitions represent a departure from, not an application of, his direct teaching.
• • Contemporary and near-contemporary Christian voices condemned these episodes on Christian grounds: Bartolomé de las Casas denounced Spanish colonial violence against indigenous peoples as a betrayal of the gospel in the 1500s; medieval canon lawyers and popes repeatedly, if inconsistently, tried to restrain crusader violence against fellow Christians and Jews en route.
• • Comparably or more lethal ideologically motivated violence in the 20th century (the atheist states of the Soviet Union and Maoist China, whose combined death tolls dwarf the Crusades and Inquisitions many times over) shows that removing religion does not remove the human capacity for ideologically justified atrocity — the relevant variable is human tribalism and the abuse of power, of which religion is one historically significant vehicle among several, not the unique cause.

Christian counterresponse

That is fair, and it is precisely why Pope John Paul II's 2000 formal apology (the 'Day of Pardon,' acknowledging historical sins including those committed 'in the service of truth' through intolerance and violence) treated these as genuine institutional wrongs requiring confession rather than defensible applications of doctrine — the tradition's own considered self-judgment, using its own sources (the Sermon on the Mount), condemns them.