In Martin Luther's 'Babylonian Captivity of the Church' (written in 1520) he developed further his sacramental theology, dealing with each of the seven sacraments in turn, but paying special attention to Baptism and the Lord's Supper.
The Babylonian Captivity was likened to a "deadly dagger aimed at the very heart of sacramentalism and clericalism and monasticism. It was the most devastating assault Luther had yet undertaken against Roman teaching and practice. It marked Luther's final and irrevocable break with the church of Rome."
"Both sides of the controversy took the book very seriously. In ducal Saxony it was rigorously suppressed. Before the imperial council at Worms, the middle of December, 1520, and again at the imperial diet the following February, the papal nuncio Aleander bitterly assailed the Captivity as completely blasphemous because it questioned the authority of the pope. John Glapion, the father confessor of Charles V, declared that it shocked him from head to foot. Erasmus now saw that his efforts to restore peace in the church would be futile: "The breach is irreparable." The University of Paris promptly condemned the document. One of Luther's most bitter enemies, Thomas Murner, translated it into German, confident that it would expose Luther to the rank and file of the people as a radical heretic and dangerous foe of the church. Of special significance was the action of Henry VIII of England. Not content with ordering Luther's writings to be publicly burned in London, he also turned theologian and wrote a book of 78 quarto pages dedicated to the pope, denouncing Luther and defending the Catholic positions on the sacraments. Henry's book so pleased the pope that he issued a special bull declaring that it was written with the help of the Holy Spirit, granting an indulgence of ten years to everyone who would read it, and bestowing upon Henry and his successors the title "Defender of the Faith."
On the other hand, the Captivity cleared the atmosphere for many thoughtful people and brought Luther not a few friends. The most outstanding example of this was John Bugenhagen, who had previously regarded Luther as a reckless heretic, but on reading through the Captivity
was completely converted to the cause of the Reformation and became one of Luther's ablest co-workers in the movement."
Source: Luther's Works, American Edition, Volume 36, page 8 -9.