The Treatise on the Power and Primacy of the Pope (1537) (Latin, ), The Tractate for short, is the seventh Lutheran credal document of the Book of Concord. Philip Melanchthon, its author, completed it on February 17, 1537 during the assembly of princes and theologians in Smalcald.
The Tractate was ratified and subscribed by this assembly as an appendix to the Augsburg Confession, which did not have a specific article dealing with the office of the papacy. Defining their stance on the papacy was deemed important by the Lutherans as they faced the impending church council that would ultimately meet as the Council of Trent. The Tractate historically was considered part of Luther's Smalcald Articles because both documents came out of the Smalcald assembly and the Tractate was placed after the Smalcald Articles in the Book of Concord.
Melanchthon used much the same rhetorical style in The Tractate as he did in the (1531): both were originally written in Latin. Melanchthon used biblical and patristic material to present and support three main points: 1) the pope is not head of the Christian Church and superior to all other bishops by divine right (de iure divino), 2) the pope and bishops do not hold civil authority by divine right, 3) the claim of the BullUnam sanctam (1302) that obedience to the pope is necessary for salvation is invalid since it contradicts the doctrine of justification by faith. Luther's position that the claims of the papacy undermine the Gospel is set forth in this treatise as the position of the Lutheran laity and clergy, and it achieved "confessional" or "symbolic" status rather quickly: the authoritative teaching of what would become the evangelical Lutheran Church.