How the First Crusade Began

A Pope With a Problem

In November 1095, Pope Urban II stood before a large crowd at the Council of Clermont in southern France and delivered a speech that changed the world. He called on Christian knights to travel to the Holy Land and take Jerusalem back from Muslim rule. The response was overwhelming — crowds reportedly shouted "Deus vult!" ("God wills it!") before he had finished speaking. Within months, hundreds of thousands of people were on the move toward the Middle East.

But the speech didn't come from nowhere, and the motivations behind it were considerably more tangled than the official version suggests. To understand why Urban called the Crusade, you need to understand the political crisis he was already managing — and why sending Europe's most violent men on a long journey east looked like a solution to it.

The Byzantine Letter That Started Everything

In early 1095, Emperor Alexios I Komnenos of Byzantium sent envoys to Urban II with a request for military assistance. The Byzantine Empire was in serious trouble. The Seljuk Turks, who had decisively defeated a Byzantine army at the Battle of Manzikert in 1071, now controlled most of Anatolia — the heartland of Byzantine territory. Alexios needed soldiers, and he hoped to recruit mercenaries from western Europe.

What Alexios wanted was a controllable force of professional fighters he could use to push the Seljuks back from Byzantine borders. What Urban delivered was something else entirely: a mass popular movement animated by religious fervor, motivated by the promise of spiritual rewards, and aiming at Jerusalem — a city that was not even Alexios's primary concern. The gap between what was requested and what was provided would cause serious problems for the next two centuries.

Urban's Actual Agenda

Urban II was a skilled political operator dealing with multiple crises simultaneously. The most pressing was the Investiture Controversy — a decades-long conflict between popes and Holy Roman Emperors over who had the right to appoint bishops and abbots. This conflict had produced an anti-pope (Clement III, backed by Emperor Henry IV), split the Church, and left Urban's authority contested even within Christendom.

He was also managing endemic violence among the European nobility. The code of chivalry was aspirational at best. In practice, knights and their retinues regularly pillaged, burned, and murdered across the European countryside. The Peace of God and Truce of God movements — Church attempts to limit noble warfare — had enjoyed limited success. A Crusade offered an alternative: redirect the violence outward, give it a sacred purpose, and get the most dangerous men in Europe focused on something other than each other.

Calling the Crusade also served Urban's immediate political interests. It demonstrated that the papacy, not the Emperor, could mobilize all of Christendom. It built relationships with the French nobility who were his core supporters. And it offered the possibility — if successful — of a massive increase in papal prestige. There were spiritual motivations too: Urban genuinely believed in the pilgrimage tradition and the sanctity of Jerusalem. But the political calculations were real and documented in his own correspondence.

The Speech at Clermont

We don't have an exact record of what Urban said at Clermont. Several chroniclers wrote down accounts of the speech, but they did so years after the fact, and their versions differ significantly. What the accounts agree on is the broad structure: Urban described the suffering of Christians in the East, invoked the sacred status of Jerusalem, and offered a spiritual incentive — remission of sins for those who took the cross.

That last element was decisive. The promise was not quite what later theology would call a "plenary indulgence," but it functioned similarly: those who died on Crusade would be treated as martyrs. For an audience that understood hell as a literal destination and lived under the constant anxiety of sin, this was not a minor offer. It was the most powerful spiritual motivator Urban could deploy.

He also invoked the image of an embattled Jerusalem, which had been under Muslim rule since 638 CE. That's worth noting: Jerusalem had been under Islamic governance for over 450 years before the First Crusade. The political change Urban was describing as an urgent emergency was nearly half a millennium old. What had actually changed was the specific regime in power — the Seljuks, unlike some earlier Muslim rulers, were making pilgrimage to Jerusalem more difficult and dangerous for Christians. That was the proximate trigger. But Urban framed it as an existential crisis of Christendom, and his audience accepted that frame.

The People's Crusade: The Disaster Before the Crusade

Before the main military force assembled, a preliminary wave of crusaders set out in the spring of 1096. They were led primarily by a charismatic preacher named Peter the Hermit and a French knight named Walter Sans-Avoir (Walter the Penniless). This People's Crusade was composed largely of peasants, minor knights, and poor pilgrims who had no military organization, no supply chain, and no realistic plan.

On the way through Europe, segments of this force attacked Jewish communities in the Rhineland — Worms, Mainz, Cologne — killing thousands in what historians call the Rhineland Massacres of 1096. The reasoning, such as it was: if they were traveling to fight the enemies of Christ in the East, why not kill the "enemies of Christ" at home first? It was the first major pogrom in medieval Europe and a preview of the violence the Crusade movement would unleash.

The People's Crusade reached Byzantine territory in terrible condition, having pillaged their way across Hungary (whose rulers were not amused). Alexios shipped them across the Bosphorus into Anatolia as quickly as possible. There the Seljuks annihilated them at the Battle of Civetot in October 1096. Peter the Hermit survived. Most of his followers did not.

The Main Crusade: Who Actually Went

The proper military crusade assembled through late 1096 and early 1097. It consisted of several distinct armies led by major European nobles: Godfrey of Bouillon, his brother Baldwin of Boulogne, Bohemund of Taranto, Raymond IV of Toulouse, Hugh of Vermandois, and Robert of Normandy, among others. Total numbers are disputed — medieval chronicles are unreliable on this point — but modern estimates suggest 60,000 to 100,000 people, including fighting men, servants, pilgrims, women, and camp followers.

These men had different motivations. Some were genuinely driven by religious conviction. Some were younger sons with no inheritance in Europe, for whom the Crusade offered land and lordship in the East. Some came for the plunder. Some came because their lord was going and they had no choice. The Crusade was not a monolith of religious enthusiasm — it was a coalition of interests that the religious frame temporarily unified.

The Long March to Jerusalem

The Crusaders' route took them through Byzantine territory, into Anatolia, through Syria, and down the coast of the Levant. Major engagements included the Siege of Nicaea (1097), the Battle of Dorylaeum (1097), the brutal eight-month Siege of Antioch (1097-1098), and finally the Siege of Jerusalem (1099). The march took three years and cost enormous numbers of lives — to combat, disease, starvation, and heat.

The Siege of Antioch was particularly harrowing. The Crusaders surrounded the city for eight months in difficult conditions. When they finally breached the walls and entered the city, a massive Seljuk relief army arrived and besieged them inside it. The discovery — possibly genuine, possibly fabricated — of the Holy Lance (supposedly the spear that pierced Christ's side at the crucifixion) inspired a desperate sortie that, against all odds, broke the Muslim siege. The story of Antioch encapsulates the First Crusade: extreme suffering, improbable survival, and an outcome that participants attributed to divine intervention.

Jerusalem: The Siege and the Massacre

The Crusaders arrived outside Jerusalem on June 7, 1099. The city was defended by a Fatimid Egyptian garrison — the Fatimids had actually taken Jerusalem from the Seljuks just a year earlier, and had sent envoys to the Crusaders proposing a partition of influence that the Crusaders rejected. The siege lasted five weeks. On July 15, 1099, the Crusaders breached the walls.

What followed was a massacre. Contemporary Christian accounts described the slaughter approvingly, comparing it to the judgment of God. Muslim, Jewish, and Arabic Christian inhabitants were killed indiscriminately. The Jewish community that had sought refuge in a synagogue was burned alive inside it. Bodies piled in the streets. The chronicler Raymond of Aguilers, writing in the victorious camp, described men riding through blood up to their horses' bridles — an image borrowed from the Book of Revelation, applied as praise to what had just happened.

Modern historians debate the exact scale of the killing. Some sources suggest tens of thousands; the actual number depends on the city's population at the time, which is uncertain. What is not in dispute is that the massacre was systematic, celebrated by the Crusaders as evidence of God's favor, and burned into Islamic historical memory in a way that still has consequences today.

What the First Crusade Created

The immediate product was the Crusader States: the Kingdom of Jerusalem, the County of Edessa, the Principality of Antioch, and the County of Tripoli. These were European-style feudal states planted in the Levant, sustained by ongoing immigration from Europe and perpetual military conflict with their neighbors. Jerusalem itself remained in Crusader hands until 1187, when Saladin retook it.

The longer-term consequences are harder to summarize. The Crusades intensified the split between Eastern and Western Christianity — Alexios never got what he actually wanted, and Byzantine relations with the Latin West deteriorated steadily until the Fourth Crusade sacked Constantinople in 1204. They hardened Islamic attitudes toward Christian Europe in ways that shaped the political culture of the Middle East for centuries. And they established a model of religiously sanctioned violence against non-Christians that was applied repeatedly in subsequent centuries — against Muslims, Jews, and eventually European Christian heretics as well.

The speech at Clermont lasted perhaps an hour. Its consequences lasted the better part of a millennium.