One of three important treatises written in 1520 ( Address To the Nobility of the German Nation , and The Babylonian Captivity of the Church , being the others), following the publication of his 95 Theses, (1517) and the Heidelberg and Leipzig disputations (1518-19). The rift between Luther and the Established Church had become great - he was called to answer charges of heresy, and meetings with two papal representatives took place in 1518-19. One of these men, Karl von Miltitz, encouraged Luther to write a conciliatory letter to the Pope (Leo X), and in the fall of 1520 Luther agreed.
In addition to the letter, a devotional pamphlet was attached - this treatise on Christian freedom, which states concisely the evangelical teaching of justification by faith alone. In the letter, Luther addresses the Pope respectfully, but as an equal, unapologetic for his doctrinal views. Luther was already in the process of being excommunicated, the Bull going into effect in 1521.