On 6 January 1420 John was present in the Reichstag of Breslau (Wrocław), where he spent a major disincentive to the Polish sentence in the process against the Teutonic Order.

For this reasons, he married around 19 March 1408 with Elizabeth (d. 22 February/27 December 1424), widow of the powerful Polish magnate Spytek II of Melsztyn and daughter of Emeric I Lackfi, General Starost of Ruthenia, Ban of Dalmatia (Transylvanian Voivodship) and of Hungary.

Moreover, despite the hostile politics of King Sigismund, Elizabeth successfully continued with her many Polish contacts, even after her remarriage with the Duke of Münsterberg.

Initially, seeing no chances of victory, Duke Louis II of Brieg entered into an arrangement with John, under which he was compelled to not interfere with the movements of enemy troops.

John died on 27 December 1428 in the battle of Altwilmsdorf (Stary Wielisław), in the Valley of Glatz (Kłodzko), fighting against the Hussite leader Jan Kralovca.