On the reforms of Pope St. Gregory VII (c. 1080) 

It really was a reform, undertaken from the highest motives and having the healthiest results; it conducted a searching inquisition against simony or the financial corruption of the clergy; it insisted on a more serious and self-sacrificing ideal for the life of the parish priest. But the very fact that this largely took the form of making universal the obligation of celibacy will strike the note of something which, however noble, would seem to many to be vaguely negative. The third example is in one sense the strongest of all. For the third example was a war; a heroic war and for many of us a holy war; but still having all the stark and terrible responsibilities of war. There is no space here to say all that should be said about the true nature of the Crusades. Everybody knows that in the very darkest hour of the Dark Ages a sort of heresy had sprung up in Arabia and become a new religion of a military but nomadic sort; invoking the name of Mahomet. Intrinsically it had a character found in many heresies from the Moslem to the Monist. It seemed to the heretic a sane simplification of religion; while it seems to a Catholic an insane simplification of religion, because it simplifies all to a single idea and so loses the breadth and balance of Catholicism. Anyhow its objective character was that of a military danger to Christendom and Christendom had struck at the very heart of it, in seeking to reconquer the Holy Places. The great Duke Godfrey and the first Christians who stormed Jerusalem were heroes if there were any in the world; but they were the heroes of a tragedy.

Now I have taken these two or three examples of the earlier medieval movements in order to note about them one general character, which refers back to the penance that followed paganism. There is something in all these movements that is bracing even while it is still bleak, like a wind blowing between the clefts of the mountains. That wind, austere and pure, of which the poet speaks, is really the spirit of the time, for it is the wind of a world that has at last been purified. To anyone who can appreciate atmospheres there is something clear and clean about the atmosphere of this crude and often harsh society. Its very lusts are clean; for they no have longer any smell of perversion. Its very cruelties are clean; they are not the luxurious cruelties of the amphitheatre. They come either of a very simple horror at blasphemy or a very simple fury at an insult. Gradually against this grey background beauty begins to appear, as something really fresh and delicate and above all surprising. Love returning is no longer what was once called platonic but what is still called chivalric love. The flowers and stars are have recovered their first innocence. Fire and water are felt to be worthy to be the brother and sister of a saint. The purge of paganism is complete at last.  For water itself has been washed. Fire itself has been purified as by fire. Water is no longer the water into which slaves were flung to feed the fishes. Fire is no longer that fire through which children were passed to Moloch. Flowers smell no more of the forgotten garlands gathered in the garden of Priapus; stars stand no more as signs of the far frigidity of gods as cold as those cold fires. They are like all new things newly made and awaiting new names, from one who shall come to name them. Neither the universe nor the earth have now any longer the old sinister significance of the world. They await a new reconciliation with man, but they are already capable of being reconciled. Man has stripped from his soul the last rag of nature worship, and can return to nature. — from St. Francis of Assisi (1923)