Now, Jan's ambitions focused on recovering the Bishopric of Włocławek, and he was named a bishop one year later in 1402. He remained in this post until his death. The Włocławek hierarchy was not easy, mainly because the Diocese was positioned in the middle of disputes between the Teutonic Order and the Kingdom of Poland, especially over who was the real owner of the Diocese of Gdańsk Pomerania (in fact, the Diocese was part of the Bishopric of Włocławek). This conflict made ruling almost impossible for Jan. As a result, he became increasingly willing to cooperate with Poland; this was particularly revealed in 1410 during the Polish–Lithuanian–Teutonic War, when thanks to the mediation of Bishop of Gdańsk, he paid homage to the Polish king.