A movement with no obvious date of birth
The First Crusade is usually dated to 1095, but its roots go back decades. Nothing in the eleventh century made it inevitable. Instead, several developments in the Western church, in Western society and in the eastern Mediterranean came together at a moment when a skilled and determined pope was ready to act. This article covers the build-up. The wider list of causes is treated elsewhere.
The Byzantine problem
In 1071 the Byzantine army was defeated by the Seljuk Turks at the Battle of Manzikert. The loss itself was not the end of the empire, but the following years saw civil conflict and the loss of much of Anatolia to Turkish groups. When Alexios I Komnenos took the throne in 1081, he worked to stabilize the empire and looked for soldiers. The Byzantine Empire had a long record of hiring Western mercenaries, including Normans, and Alexios turned to the West for the same sort of help.
According to later sources, envoys from Alexios appeared at a church council at Piacenza in 1095 and asked for aid. The accounts differ, and it is unclear exactly how large or specific the request was. What seems likely is that the emperor wanted trained fighting men under his own command, not an independent army of pilgrims. That difference would cause problems later.
Church reform and papal confidence
The second thread was within the church. In the later eleventh century, reforming popes worked to reduce lay interference in church appointments and to strengthen the pope’s authority. A pope who could claim to direct Christian society was in a position to call on knights as well as clergy. The conflict with the German emperor over appointments, known as the investiture controversy, was in full swing, and a popular cause could help the papacy’s standing. In 1054 a split between the Roman and Greek churches had occurred, though contemporaries did not see it as final, and Urban II may have hoped that helping the East would improve relations.
Peace movements and the warrior class
In parts of France and elsewhere, church leaders had been organizing movements that tried to limit violence, protecting churches, peasants and clergy and discouraging fighting on holy days. These ideas encouraged the notion that the church could regulate warfare and direct it to good ends. Urban’s message could be understood in that context: if knights were to fight, let them fight for a cause the church approved. Historians sometimes argue that this redirected violence outward, though how far that was an intended goal is debated.
Pilgrimage and holy places
Pilgrimage to Jerusalem had grown in the eleventh century, and some travelers returned with stories of difficulty and danger. These stories were useful to preachers. There was also lingering memory of the destruction of the Church of the Holy Sepulchre in 1009 under a Fatimid ruler, although it was rebuilt, and Christians continued to visit. In the Mediterranean, the Normans in Italy and Sicily and Christian rulers in Spain were fighting Muslim states, which showed that war against Muslim powers could be presented as a religious cause.
Clermont, 1095
In November 1095 Urban II addressed a council at Clermont in France. There is no reliable verbatim record of the speech. The surviving versions were written after the First Crusade had succeeded, and they are shaped by that outcome. Even so, it is widely accepted that Urban called on Western warriors to go to the aid of Christians in the East and to free Jerusalem, and offered a spiritual reward for those who went. Whether Jerusalem was the main objective from the start, or became so as preaching spread, is debated.
Spreading the word
Urban toured France in the months after Clermont, preaching and arranging for others to do the same. The response was larger than he seems to have expected. Nobles, knights and also many poor people took the cross. Popular preachers such as Peter the Hermit gathered crowds that set out in 1096 before the organized armies, with poor results. The main armies, under leaders such as Raymond of Toulouse, Godfrey of Bouillon and Bohemond of Taranto, set out later that year.
What the build-up shows
The rise of the crusades was the product of a request from the East, a confident reforming papacy, a warrior society with a taste for pilgrimage and a set of ideas about sacred war that had been developing for some time. The movement then took on a life that its originators did not fully control, which is a theme that runs through its later history.