[1] Together with other Bohemian preachers and writers of that time, he paved in a certain sense the way for the reforming activity of Jan Hus.
In December 1363 he resigned all his appointments that he might become a preacher pure and simple; he addressed scholars in Latin, and (an innovation) the laity in their native Czech, or in German, which he learnt for the purpose.
The success of his labors made itself apparent in the way in which he transformed the ill-famed Benátky ("Venice") street in Prague Old Town quarter into a benevolent institution, Nový Jeruzalém ("New Jerusalem").
He affixed to the gate of St. Peter's a placard announcing his sermon, but before he could deliver it was thrown into prison by the Inquisition.
Urban, however, on his arrival, ordered his release, whereupon he returned to Prague, and from 1369 to 1372 preached daily in the Týn Church there.