The period of joint rule of the princes faced several difficulties, the most importante of them was the loss of part of Greater Poland in favor of Władysław I the Elbow-high.

In 1328, John supported the inhabitants of Brzeg-Legnica in the fight against Bolesław III the Generous and Henry VI the Good; however, this war caused significant areas of devastation outside Lower Silesia.

According to the treaty signed between the brothers in 1326, all his lands (with the exception of the city of Głogów, who passed to Przemko II's widow Constance as her dower) were divided between John and Henry IV.

At the same time, Władysław I the Elbow-high take advantage with the reigning confusion and occupied the Greater Poland lands who still remained under the hands of Henry III's sons after 1314.

In order to avoid sells or divisions, on 27 August 1337, Henry IV and Conrad I purchased to John all his Duchy of Ścinawa, but he could retain the sovereignty during his life.

Despite all these efforts to maintain the unity of the Duchy, shortly after, and probably with the consent of the brothers, John sold the Bohemia Góra Śląska (the town was soon recovered in unknown circumstances, and re-sold in 1345 for 1,500 fines).

In 1343, during the war between Henry V and King Casimir III the Great, John supported militarily his nephew, so that when the Polish army entered in Silesia, Ścinawa was sieged and plundered.