Thomas Mann called the Thuringian humanist and theologian Johannes Crotus Rubianus (1480 to about 1540) a man of the most educated love of peace. Despite this, Crotus kept getting caught up in the intellectual and religious debates of the time. In the so-called "Reuchlin dispute" he sided with the embattled Hebraist Johannes Reuchlin with his ingenious satire of the "letters of obscurity". In 1521 he, the passionate follower of Martin Luther, received the reformer, who had already been banned, as rector of the University of Erfurt. In the second half of the 1920s he served in an important position for the Prussian Duke Albrecht, who had transformed the former Teutonic Order territory into a Lutheran state. However, disillusioned with the development of the Lutheran Reformation, he returned to the old faith in 1530 and became a councilor and canon in the Neue Stift zu Halle, founded by the Archbishop of Mainz. He was known by the Lutherans as "Dr. toad, the cardinal's plate licker". Eckard Bernstein evaluated the contemporary letters from and to Crotus as well as numerous other documents from this period of religious upheaval and upheaval. He thus succeeds in writing the first well-founded biography of the brilliant Thuringian satirist, highly educated humanist and theologian Johannes Crotus Rubianus, which takes into account the temporal context.