Hymnologists have their favorites among the sacred singers of the Middle Ages, but all concede the first place to the poet who gave the world the _Dies Irae_, the great sequence or “prose” sung in the service for the dead of the Latin Church. It has attracted more attention than any other single hymn. Whole books have been written about it. It is indissolubly associated in the history of music with Mozart’s wonderful “Requiem,” and in that of literature with the concluding scenes of the first part of “Faust.” More translations have been made of it than of any other poem in the Latin language, or perhaps in any language. All Christendom rejoices in it as a common treasure, the gift of God through a devout Italian monk of the thirteenth century. It was in an age full of vitality that this “hymn of the giants” was written—the most interesting century in the history of Christendom, Matthew Arnold says. In all directions we encounter the play or collision of great forces. The Papacy, the Empire, the Crusades, the Mendicant Orders, and even, in its way, the Inquisition, give evidence of the working of a spirit of energy and movement, which places the century in sharp contrast to the less explicit development which had preceded, and the age of comparative exhaustion which followed. Nowhere was this more visible than in the characters of the great Churchmen of the thirteenth century. Popes like Innocent III. and Gregory IX., founders of orders like Dominic and Francis, theologians like Aquinas and Bonaventura, may excite our admiration or our censure, but they are men of such magnitude as are not to be found in other centuries in the same number. They were live men, and they have made a lasting impression upon the world by the force of their vitality.