Crusades

==Crusading movement==
{{Main|Crusading movement}}
Prior to the 11th{{nbsp}}century, the [[Latin Church]] had developed a system for the remission and absolution of sin in return for contrition, confession, and penitential acts. Reparation through abstinence from martial activity still presented a difficulty to the noble warrior class. It was revolutionary when Gregory VII offered absolution of sin earned through the Church-sponsored violence in support of his causes, if selflessly given at the end of the century.{{sfn|Tyerman|2011|p=61}}{{sfn|Latham|2012|p=123}} This was developed by subsequent Popes into the granting of plenary indulgences that reduced all God-imposed temporal penalties.{{sfn|Maier|2006a|pp=627–629}} The papacy developed "Political [[Augustinianism]]" into attempts to remove the Church from secular control by asserting ecclesiastical supremacy over temporal polities and the Orthodox Church. This was associated with the idea that the Church should actively intervene in the world to impose "justice".{{sfn|Latham|2012|p=118}}

A distinct ideology promoting and regulating crusading is evidenced in surviving texts. The Church defined this in legal and theological terms based on the theory of holy war and the concept of pilgrimage. Theology merged the Old Testament Israelite wars instigated and assisted by God with New Testament Christocentric views. Holy war was based on ancient ideas of just war. The fourth-century theologian [[Augustine of Hippo]] had Christianised this, and it eventually became the [[paradigm]] of Christian holy war. Theologians widely accepted the justification that holy war against pagans was good, because of their opposition to Christianity.{{sfn|Maier|2006a|pp=627–629}} The Holy Land was the patrimony of Christ; its recovery was on behalf of God. The Albigensian Crusade was a defence of the French Church, the Northern Crusades were campaigns conquering lands beloved of Christ's mother [[Mary, mother of Jesus|Mary]] for Christianity.{{sfn|Maier|2006a|pp=629–630}}

Inspired by the First Crusade, the crusading movement went on to define late medieval western culture and impacted the history of the western Islamic world.{{sfn|Riley-Smith|1995|pp=4–5, 36}} Christendom was geopolitical, and this underpinned the practice of the medieval Church. Reformists of the 11th{{nbsp}}century urged these ideas which declined following the Reformation. The ideology continued after the 16th{{nbsp}}century with the military orders but dwindled in competition with other forms of religious war and new ideologies.{{sfn|Maier|2006a|pp=630–631}}