[1] He was the son of Václav of Janow, a Bohemian knight, and began his studies at the University of Prague, before leaving to complete them in Paris.
Between 1388 and 1392, he wrote several essays, which were later collected and entitled Regulae Veteris et Novi Testamenti ("Principles of the Old and the New Testaments").
He advocated the removal of saints and their relics from the churches, because of the abuses he witnessed involving their veneration.
At the Synod of Prague in 1389 such encouragement of daily Communion was prohibited, and the veneration of images defended.
Janow retracted his views and swore repeatedly that he had unfailing loyalty towards the Catholic Church; therefore, he was not punished.