Alienated by this and by the dogmatism and intolerance of Luther's writings, Erasmus finally defined his position in a _Diatribe on Free Will_.

[Sidenote: 1524] As Luther's theory of the bondage of the will was but the other side of his doctrine of justification by faith only--for where God's grace does all there is nothing left for human effort--Erasmus attacked the very center of the Evangelical dogmatic system.

The question, a deep psychological and metaphysical one, was much in the air, Valla having written on it a work published in 1518, and Pomponazzi having also composed a work on it in 1520, which was, however, not published until much later.

It is noticeable that Erasmus selected this point rather than one of the practical reforms advocated at Wittenberg, with which he was much in sympathy.

Luther replied in a volume on _The Bondage of the Will_ reasserting his position more strongly than ever.