"We can see St. Francis of Assisi, for example, as he is revealed to us by the biographies of Thomas of Celano or Bonaventure. They greatly overstress the supernatural aspect of his character and the image they create remains remote from the world of men. Again, we can see him as Sabatier portrayed him. Here we have a concrete picture of his life, it is true, but the essence, the heart of the saint has vanished. This is because Christ has gone out of the picture too. For, along with Francis of Assisi, Christ also is classified as one of a series of individuals belonging to the same psychological type, that of the "homo religiosus". This train of thought finally becomes lost in the rationalism and lyricism of a Henry Thode, Hermann Hesse, or Nikos Kazantzakis. We are today engaged in the task of penetrating to the true nature of Francis, who lived in the mystery of a likeness to Christ such as, perhaps, no other individual has ever achieved in such charismatic exactness. For that very reason he possessed so definite and so unique a human personality that he was able to influence history as few others have been able to."Guardini - The Humanity of Christ
With the humanity of Francis in perspective, it is profitable to read this account of Francis and the Sultan in Commonweal magazine. It's an interesting article which delineates many of the historical factors in the meeting between the two men even as it tends to reduce Francis's mission to a simplistic one of peace and solidarity with the poor.