Defenders
Byzantine Empire
Led by:
- Constantine XI Palaiologos (1405–1453)
The defenders consisted of:
- Byzantine Greek soldiers.
- Local militia and volunteers.
- Monks and civilians helping with the defense.
- Small contingents from various Christian states.
A particularly important allied force was:
- Giovanni Giustiniani (1418–1453)
Giustiniani brought several hundred heavily armed Genoese troops and directed much of the defense of the land walls.
Total defenders are generally estimated at about 7,000–8,500 men.
Attackers
Ottoman Empire
Led by:
The Ottoman army included:
- Professional infantry.
- The elite Janissary corps.
- Cavalry.
- Engineers.
- Naval forces blockading the city.
Estimates vary, but the attacking force was likely 50,000–80,000 men, with some contemporary sources claiming even higher numbers.
A key advantage was massive artillery, including the famous giant cannon designed by:
These bombards helped breach the formidable Theodosian Walls that had protected the city for nearly a thousand years.
Why the Battle Mattered
The city was the capital of the Byzantine Empire, itself the surviving eastern half of the Roman Empire.
When Constantinople fell:
- The Byzantine Empire effectively ended.
- The last Roman emperor, Constantine XI, was killed in the fighting.
- The Ottomans gained control of one of the most strategically important cities in the world.
- Constantinople became the Ottoman capital and eventually evolved into modern Istanbul.
The Larger Civilizational Context
Many contemporaries interpreted the conflict as:
- Christianity vs. Islam,
- Europe vs. the Ottoman world,
- Rome's final collapse.
Modern historians tend to see it more broadly as:
- the end of the medieval Eastern Roman state,
- the rise of Ottoman imperial power,
- a major shift in Mediterranean and Eurasian geopolitics.
For Nicholas of Cusa (1401–1464), the fall was not merely a military event. It became the immediate catalyst for On the Peace of Faith, where he asked whether religious conflict must inevitably lead to catastrophe, or whether some deeper basis for coexistence could be found beneath competing faiths.
Ed: Were there not crusades organized to retake the city? I’m forgetting the details but Will Durant talked about “Christians killing Christians,” that more were killed in this struggle than had died as martyrs during the Roman persecution in the West. What am I recalling here?
Chat: I think you're remembering two related but distinct historical episodes, and they are easy to blend together because both involve Constantinople, crusades, and Christians fighting Christians.
1. The Fourth Crusade (1202–1204) — Probably What Durant Was Referring To
This is the famous scandal.
The crusaders were originally supposed to attack Muslim-controlled territories in the Holy Land. Instead, through a complicated mix of debt, politics, and opportunism, the crusading army turned against fellow Christians.
In 1204, Western European crusaders captured and sacked Constantinople, the capital of the Christian Byzantine Empire.
The result was catastrophic:
- Churches were looted.
- Monasteries were pillaged.
- Relics were stolen.
- Civilians were killed.
- The city was devastated economically and culturally.
Many contemporaries regarded it as one of the greatest crimes in Christian history.
The Byzantine Empire never fully recovered from the sack.
This event permanently deepened the division between:
- the Latin Christian West (Roman Catholic),
- the Greek Christian East (Orthodox).
When Will Durant speaks of "Christians killing Christians," this is very likely the event he had in mind.
2. The Fall of Constantinople (1453)
This occurred 249 years later.
Here the combatants were:
- Byzantine Christians defending the city.
- Ottoman Muslims attacking it.
This was not Christians fighting Christians.
However, many Byzantines felt bitter that Western Europe had failed to provide adequate assistance.
Some aid arrived from Venice, Genoa, and elsewhere, but nothing remotely sufficient to stop Sultan Mehmed II.
Thus, the memory of the Fourth Crusade still hung over relations between East and West when the city finally fell.
Were There Crusades to Retake Constantinople After 1453?
Yes, there were repeated proposals and a few attempts.
Popes, princes, and humanists called for crusades against the Ottomans.
Among those advocating responses was Nicholas of Cusa (1401–1464) himself.
However, Europe was divided:
- France and England had recently emerged from the Hundred Years' War.
- Italian states competed with one another.
- The Holy Roman Empire lacked unity.
- Various rulers had conflicting priorities.
As a result, no large-scale crusade successfully recovered Constantinople.
The Ottoman position only strengthened over time.
The Irony That May Have Struck Cusa
One reason On the Peace of Faith is so remarkable is that it was written immediately after the fall of Constantinople.
Many intellectuals responded by asking:
"How do we defeat the Turks?"
Cusa asked a different question:
"How do religions come into conflict in the first place?"
That does not mean he ceased being a loyal churchman or ceased believing Christianity true.
But instead of writing a military strategy, he wrote a visionary dialogue about religious reconciliation.
That was an unusual response in 1453.
About Durant's Remark on Martyrs
If memory serves, Durant was making a rhetorical comparison rather than citing a precise demographic calculation.
A recurring theme in his histories is that:
Christians often inflicted more suffering on one another through schisms, religious wars, persecutions, crusades, and political struggles than they had suffered under the pagan Roman emperors.
The Fourth Crusade's sack of Constantinople became one of his favorite examples because it dramatized the tragedy so vividly:
The greatest Christian city in the East was not destroyed by Muslims but first devastated by fellow Christians.
That event haunted Eastern Orthodox memory for centuries and helps explain why relations between Eastern and Western Christianity remained strained long after 1204. In a sense, when Constantinople fell in 1453, some Byzantines felt that the wound inflicted by the Fourth Crusade had never fully healed.
Ed: What happened to the Church in the city after the Fall? It seems that it coexisted with the Islamic faith. Is this the situation that continued to the present day?
Chat: Yes, broadly speaking, that is what happened, though the story is more complex than simple coexistence.
When Constantinople fell in 1453, the Ottoman rulers did not abolish Eastern Christianity. In fact, Sultan Mehmed II quickly reestablished the office of the Orthodox Patriarch.
This surprised many Western Christians.
The Ottoman state generally preferred:
- political obedience,
- tax revenue,
- social stability,
rather than forced conversion of every subject.
As a result, the Orthodox Church survived.
The Millet System
The Ottoman Empire eventually organized non-Muslim communities into what historians call the millet system.
Under this arrangement:
- Muslims remained the ruling community.
- Christians and Jews were allowed to practice their faith.
- Religious communities governed many of their own internal affairs.
- Patriarchs and religious leaders acted as intermediaries with the state.
Orthodox Christians paid special taxes and occupied a subordinate legal position, but they were not eradicated.
Thus the relationship was neither full equality nor constant persecution.
It was a form of tolerated subordination.
An Historical Irony
Many Orthodox Christians came to view Ottoman rule as less threatening to their faith than some earlier Western interventions.
After the Fourth Crusade of 1204, memories of Latin occupation remained bitter.
A famous phrase, probably reflecting sentiments held by some Byzantines before 1453, was:
"Better the Turkish turban than the Latin mitre."
The phrase does not mean people preferred Islamic theology.
It means some feared domination by Western Christians more than political rule by Muslim authorities.
That tells you how deep the wounds of 1204 ran.
What Happened to the Patriarch?
The office survived.
The leader of Eastern Orthodoxy continued to reside in Constantinople, now renamed and gradually transformed into modern Istanbul.
Today the office is held by the Bartholomew I.
The Ecumenical Patriarch no longer possesses political authority comparable to the Byzantine era, but remains the symbolic "first among equals" within the Eastern Orthodox world.
Thus there is a direct institutional continuity from before 1453 to the present.
Did Christianity Survive in Anatolia?
For centuries, yes.
The Ottoman Empire contained:
- Greeks,
- Armenians,
- Assyrians,
- Slavs,
- Arabs,
many of whom were Christian.
Large Christian populations continued to exist throughout Ottoman territory for hundreds of years.
The major reduction came much later, especially during the late nineteenth and early twentieth centuries through:
- wars,
- population exchanges,
- nationalism,
- forced migrations,
- massacres and expulsions.
As a result, regions that had been heavily Christian for over a millennium became overwhelmingly Muslim.
Did Christianity and Islam Continue Side by Side?
Yes.
In fact, from 1453 onward, one could argue that the Ottoman Empire became one of history's longest-lasting experiments in large-scale religious coexistence under unequal conditions.
For roughly five centuries:
- Islam was the dominant faith.
- Orthodox Christianity persisted.
- Judaism persisted.
- Various other Christian communities persisted.
The arrangement was imperfect and often discriminatory by modern standards, but it was also more durable than many people realize.
Through the Lens of Nicholas of Cusa
This is where On the Peace of Faith becomes especially interesting.
Cusa (1401–1464) wrote immediately after the fall of Constantinople and imagined a heavenly dialogue seeking religious concord.
History did not follow his vision exactly.
The Ottoman Empire did not produce a universal religion or doctrinal unity.
What emerged instead was something more practical:
Different religions continued to exist under the same political order for centuries.
In a sense, history answered Cusa's question differently than he expected.
He sought peace through recognition of a shared truth.
The Ottoman system often achieved peace through negotiated coexistence among communities that continued to disagree.
That distinction—unity versus coexistence—is one of the enduring questions in the history of religion.