thumb|Johann Cochlaeus.
Johann Cochlaeus (Cochläus) (1479 – 10 January 1552) was a German humanist, music theorist, and controversialist.
Life
Originally Johann Dobneck, he was born of poor parents at Wendelstein (near Nuremberg), from which he obtained the punning surname Cochlaeus, for which he occasionally substituted Wendelstinus. Educated at Nuremberg by the humanist Heinrich Grieninger, he entered the University of Cologne in 1504, and there associated with Hermann von Neuenahr, Ulrich von Hutten, and other humanists. He also knew well Carl von Miltitz, who later became papal chamberlain. In 1507 he graduated; he left Cologne in May 1510 to become schoolmaster at Nuremberg, where he brought out several school manuals. his humanist ideas raised the suspicion of many Catholics, and his polemical writings won him the hatred of the Reformers.
[[File:Musica LOC Image20.jpg|thumb|alt=Leaf from Johannes Cochlaeus' Musica, 1507, printed text and musical notation woodcuts|Leaf from Johannes Cochlaeus' Musica, 1507. From the Rosenwald Collection, Library of Congress.]]
He published under the name of Wendelstein his first piece, Musica (1507).
In his Colloqium Cochlaei cum Luthero, Cochlaeus reported on his discussion with Luther on 24 April 1521 about issues, such as the origin of Luther's doctrine of predestination, the Eucharist, and the authority of the Bible. (See Plowboy trope.) After writing a series of pamphlets discussing the main themes of Luther's theology, Cochlaeus became convinced that any further argumentation with Luther was futile. Accordingly, instead of convincing Luther, Cochlaeus attempted to come to an agreement with Melanchthon at the Diet of Augsburg in 1530, but without much success. was popular and influential. It became a model and source for later
polemics, and the view expounded in it that the Protestant Reformation was nothing but an incidental jealousy between the Dominican and Augustinian orders had a wide circulation.