The Crusades were a series of religious wars initiated, supported, and sometimes directed by the Latin Church in the medieval period. The term refers especially to the Eastern Mediterranean campaigns in the period between 1096 and 1271 that had the objective of recovering the Holy Land from Islamic rule. The term has also been applied to other church-sanctioned campaigns fought to combat paganism and heresy, to resolve conflict among rival Roman Catholic groups, or to gain political and territorial advantage. The difference between these campaigns and other Christian religious conflicts was that they were considered a penitential exercise that brought forgiveness of sins declared by the church. Historians contest the definition of the term crusade. Some restrict it to only armed pilgrimages to Jerusalem; others include all Catholic military campaigns with a promise of spiritual benefit; all Catholic holy wars; or those with a characteristic of religious fervour. In 1095, Pope Urban II proclaimed the First Crusade at the Council of Clermont. He encouraged military support for Byzantine Emperor Alexios I against the Seljuk Turks and an armed pilgrimage to Jerusalem. Across all social strata in western Europe there was an enthusiastic popular response. Volunteers took a public vow to join the crusade. Historians now debate the combination of their motivations, which included the prospect of mass ascension into Heaven at Jerusalem, satisfying feudal obligations, opportunities for renown, and economic and political advantage. Initial successes established four Crusader states in the Near East: the County of Edessa; the Principality of Antioch; the Kingdom of Jerusalem; and the County of Tripoli. The crusader presence remained in the region in some form until the city of Acre fell in 1291, leading to the rapid loss of all remaining territory in the Levant. After this, there were no further crusades to recover the Holy Land. Proclaimed a crusade in 1123, the struggle between the Christians and Muslims in the Iberian Peninsula was called the Reconquista by Christians, and only ended in 1492 with the fall of the Muslim Emirate of Granada. From 1147 campaigns in Northern Europe against pagan tribes were considered crusades. In 1199 Pope Innocent III began the practice of proclaiming political crusades against Christian heretics. In the 13th century, crusading was used against the Cathars in Languedoc and against Bosnia; this practice continued against the Waldensians in Savoy and the Hussites in Bohemia in the 15th century and against Protestants in the 16th. From the mid-14th century, crusading rhetoric was used in response to the rise of the Ottoman Empire, only ending in 1699 with the War of the Holy League.
Las cruzadas fueron una serie de guerras religiosas impulsadas por la Iglesia católica durante la Edad Media. Dichas campañas militares tenían como objetivo declarado recuperar para la Cristiandad la región del Cercano Oriente conocida como Tierra Santa, la cual se encontraba bajo el dominio del Islam. Otras expediciones armadas con el propósito de conquistar territorios musulmanes previamente cristianos, como en España, de implantar el cristianismo, como en Prusia, o incluso de suprimir por la fuerza movimientos contra el poder de la Iglesia, como en el sur de Francia, también fueron conocidas finalmente como Cruzadas. Las cruzadas del Mediterráneo Oriental, las primeras a las que se les aplicó este nombre, fueron llevadas a cabo por señores feudales y soberanos de Europa Occidental, sobre todo los de la Francia de los Capetos y el Sacro Imperio Romano, pero también de Inglaterra y Sicilia, a pedido del Papado y, en principio, del Imperio de Oriente. Tuvieron lugar durante un período de casi dos siglos, entre 1096 y 1291, llevaron al establecimiento efímero de un Reino cristiano en Jerusalén y la conquista, temporal, de Constantinopla. Las guerras con sanción religiosa en España y Europa Oriental, algunas de las cuales culminaron en el siglo XV, recibieron la calificación de cruzadas por parte de la Iglesia. Se enfocaron en la lucha contra los gobernantes musulmanes de territorios españoles, contra los eslavos y bálticos paganos (prusianos y lituanos sobre todo) y en algún caso contra el Imperio Oriental o los otomanos. En la cruzada contra los albigenses la lucha fue contra cristianos disidentes y los nobles que los apoyaban, en especial contra los seguidores del catarismo. En muchos casos, las cruzadas fueron causa de persecuciones contra los judíos, cristianos ortodoxos griegos y rusos. Los participantes de las cruzadas, conocidos como cruzados, tomaban votos religiosos de manera temporal y se les concedía indulgencia por sus pecados.