Casimir I the Restorer not supported by modern historians. Regardless, he left church work for good in 1031. Casimir's father, Mieszko II, was crowned King of Poland in 1025 after the death of his father Bolesław I the Brave. However, the powerful magnates of the country feared a strong central government like the one that existed under Bolesław I's rule. This led to considerable friction between the King and the nobility. Taking advantage of the King's precarious situation, Mieszko II's older half-brother Bezprym and younger brother Otto turned against him and allied themselves with the Holy Roman Emperor Conrad II, whose forces attacked Poland
Mieszko I Tanglefoot the Sandomierz nobles captured in the battle). On 22 March 1201 Jarosław of Opole died. The Duchy of Opole was then inherited by his father Bolesław the Tall, with whom the late Duke was recently reconciled. Bolesław the Tall died only nine months later, on 7/8 December 1201, leaving all his lands to his eldest (and only) surviving son Henry I the Bearded. Mieszko was determined to obtain Opole and made a surprise attack at the beginning of 1202. The Duke managed to obtain Opole, which was from then on definitely joined to his lands. Despite this victory, Mieszko wanted