[2] The first mention of him is in 1267 as chaplain of the Bishop, Thomas Zaremba and in 1268 records state he was a Canon of Wrocław and had a master's degree, indicating a university education.
After the death of Tomasz Zaremba, Jan was elected Bishop of Wroclaw on 24 April 1292 and received Papal ascent.
According to Jan Długosz, he was supported in the election by the Polish part of the chapter, against the German factions.
In this his task was easier than that of Thomas due to the death of Prince Henryk, despite however the intrigues of Henry’s successor Bulko I, Duke of Świdnica-jaworski.
John conducted peace negotiations between Bolesław Srogim, and Rudolf II and later (1299) supported Konrad II the Hunchback in his conflict with his brother Henry Głogowczykiem Duke of Głogów.