In 1397-1398 Wenceslaus IV and his court went on journey to France, and Jan Hus accompanied him. After his return he started to lecture at the university, and in 1400 he was ordained priest.

Starting in March 1402, he was active for more than ten years as a preacher at the Betlehem Chapel, which had been established in 1391 with the express stipulation that the word of God should be proclaimed in the Czech language.

The Archbishop of Prague, Zbyněk Zajíc of Hazenburg supported Hus´s critical views at first, indeed he twice appointed him as synodal preacher for the clergy of the Prague archdiocese. But then came the disputes over Wyclif, which started in Prague University in 1403, with the Czech masters defending Wyclif while the others made him out to be a heretic. In 1406 Archbishop Zbyněk tried to put an end to these disputes by banning Wyclif´s iewss which provoked a rupture between Hus and the Archbishop.

Hus´s activities in Betlehem Chapel gave rise to sermons preached on Sundays and holy days, Czech version of some Latin mass hymns (such as Jesus Christ, generous priest), and moralist tracts such as Ten gold pieces, A small mirror for the sinner.