The Crusades

Religion and politics were intertwined with each other in manyEuropean empires in the years leading to the Crusades. TheChristian Church was going through a power struggle whicheventually led to a permanent division which exists till this day. It was known as the East-West Schism. Also called as theSchism of 1054, it marked the division of the church intoRoman Catholic churches and Eastern Orthodox churches.
Thisbreak in the churches occurred because of a difference inviewpoints related to various rituals and rules among Christians, one of the most popular ones being the use of leavened orunleavened bread for the Eucharist. This Schism of 1054 reduced the power and authority of thechurch among its followers. In an attempt to increase andreinforce the importance of the church, Pope Gregory VIIstarted a reformation which would transform the church from adecentralized religious institution to a centralized one where thePope held more power and authority.
This is known as the Gregorian Reform and played a big rolein vesting greater power to the Pope. It led to a change whereall disputes had to be referred to Rome and all appeals wereto go through the Pope as well. This automatically reduced theamount of power vested on the Bishops. The power strugglebetween the Popes and the state in the 11th and 12thcenturies is termed as the Investiture Controversy.
The focalpoint of the dispute was whether it should be the Pope or themonarch who should appoint the local church officials whichincluded the bishops and the abbots. Many people were against such regulations being set by PopeGregory VII. This led to the appointment of an alternativePope. Antipope Clement III was the archbishop of Ravenna andwas elected as a Pope in 1080 against Pope Gregory VII. While he gained a lot of popularity and had a substantialfollowing in Rome and in other parts of Europe, he isconsidered to be an anti-Pope till this day with his bodyexhumed and his remains dumped in the Tiber.
All of these events were combined with the constantadvancements of the Muslims in the Holy Land of theChristians. With the papacy going through a storm and theChristian authority being in question, it was important forChristians to protect their Holy Land. While early Arabs hadbeen tolerant when it came to Christians visiting their holy sitesas pilgrims, the Seljuk Turks who later conquered the regionsstarted showing no mercy to the pilgrims and began to createan inhospitable environment for the Christians travelling to theholy lands.
The Christians found this to be unacceptable and wanted torecapture their Holy Land. With internal disturbances within thereligion and external conflicts arising from the Muslims, theChristians felt it was important to stand their ground andreinforce the importance of the religion among all.