His eyes were opened to the iniquities of Rome by Valla's exposure of the Donation of Constantine, published by Ulrich von Hutten in 1519.

After reading it he wrote: Good heavens! what darkness and wickedness is at Rome! You wonder at the judgment of God that such unauthentic, crass, impudent lies not only lived but prevailed for many centuries, that they were incorporated into the Canon Law, and (that no degree of horror might be wanting) that they became as articles of faith.
Like German troops Luther was best in taking the offensive.

These early years when he was standing almost alone and attacking one abuse after another, were the finest of his whole career.

Later, when he came to reconstruct a church, he modified or withdrew much of what he had at first put forward, and re-introduced a large portion of the medieval religiosity which he had once so successfully and fiercely attacked.

The year 1520 saw him at the most advanced point he ever attained.