It is quite commonly assumed that the initiator of the crusades (i.e. the crusades) to the Holy Land was Pope Urban II, who at the Synod in Clermont in 1095 threw the slogan of her liberation from the hands of the infidels. As a result of a combination of various social, economic and religious reasons, this slogan fell on a very fertile ground in Latin Europe and became the cause of the first knight's crusade in the years 1096-1099. As a result of this crusade, not only was Jerusalem conquered, but also in 1100 the Kingdom of Jerusalem was established in the Middle East. Its first king was Baldwin I, although the actual "founder" of the new state was Geoffrey of Bouillon. After the first crusade, there were others, of which we can mention the third (1189-1192) or the fourth (1202-1204), which, however, did not reach the Holy Land, and led to the sacking of Constantinople by would-be crusaders. It is assumed that the end of the crusade movement to the Holy Land is the year 1291, which is the same as the conquest of the last Crusader stronghold in these areas, i.e. Akki. The importance of the crusades in the history of medieval Europe and in the history of its military was enormous. First of all, they led to a significant weakening of the Byzantine Empire, and indirectly facilitated the later expansion of the Ottoman Turks in the 14th-15th centuries. They led to a great increase in the role of Italian cities in the Levantine trade and the development of boatbuilding in the Apennine. The intellectual horizons of contemporary Europeans widened considerably. For the defense of the Holy Land, knightly orders were also established, including the Teutonic Order.