At the time of his father's death in 1230, Mieszko II and his younger brother Władysław were still minors; for this, the regency of the Duchy was taken by their mother and Henry I the Bearded, Duke of Wrocław.

A year later, to calm the erupted rebellion against this decision, Henry I the Bearded give Kalisz and Wieluń to Casimir I's sons, taking the full control over Opole-Racibórz, but without denying their hereditary rights.

Mieszko II's mother Viola and brother Władysław are expected to remain in Kalisz, which held power under the guidance of the Duke of Wrocław.

In contrast to Bolesław V the Chaste, Duke of Sandomierz, Mieszko II didn't have any intention to give up his principality at the mercy of the enemy, and stood facing them.

Further meetings between the brothers in order to find a way out of this difficulty (for example, on 25 March 1243 in Mechnicy near Koźle) didn't give positive results and in 1244, Władysław was forced to withdraw from Kalisz, maintaining only his rule over Wieluń, which ultimately also lost in 1249.

The Masovia-Opole forces were defeat, in part because the mutual distrust between both rulers, despite the fact that Mieszko II brought further retaliatory expeditions against Bolesław V the Chaste.