The first crusade

From the pontificate of Leo IX (1049-1054) to that of Urban II (1088-1099) the movement for ecclesiastical reform which had spread from small monastic centers in Italy, Burgundy, and Lorraine came to be directed by the popes themselves and thus began to focus upon the whole of the universal Church and Christendom. The result of the new universality of the ecclesiastical reform movement was the transformation of Christendom. Its most striking and complex by-product was the First Crusade. - Introduction.