Gaining his freedom at the instance of Hungarian magnates, he visited Melanchthon at Wittenberg, and in 152 4 became professor of Greek at the university of Heidelberg, being in addition professor of Latin from 1526.
Melanchthon was a lecturer here (1512-1518).
At this time, in association with the keen humanists Conrad Mutian, Crotus Rubeanus and Eoban Hess, he was of sceptical tendency; moving to Wittenberg in 1519, he became evangelical under the teaching of Melanchthon and the preaching of Luther.
Its starting-point was a dispute with Melanchthon in 1527 as to the relation between repentance and faith.
Melanchthon urged that repentance must precede faith, and that knowledge of the moral law is needed to produce repentance.