In the first years of his government, young Bolesław remained under the strong influence of his mother and Voivode Wszebor, who feared the ambition of his elder half-brother High Duke Władysław II.

Trouble began openly in 1141, when Dowager Duchess Salomea — without the consent of High Duke Władysław II — organized a meeting with her sons at her residence in Łęczyca.

Nevertheless, the final victory of Władysław seemed likely, especially after the conquest of Masovia (forcing Bolesław to escape) and the siege of Poznań in Greater Poland in the spring of 1146.

Thanks to the intrigues of his wife, Agnes of Babenberg, a half-sister of King Conrad III, Władysław II succeeded in convincing his brother-in-law to make a military expedition to Poland.

The hastily organized expedition however clashed with the reluctance of the former subjects of the deposed high duke, and was finally defeated already on the Polish border near the Oder river in August 1146.

In subsequent years, Bolesław IV along with his younger brothers bellows sought to maintain good relations with the royal House of Hohenstaufen, Władysław's allies.

To this end, in 1148 the junior dukes organized a meeting in Kruszwica, to which they invited the warlike Margrave Albert the Bear of the German Northern March (the later Margraviate of Brandenburg), who had reached the Polish border in the course of the Wendish Crusade.

However, one year later, and again instigated by the intrigues of Władysław's wife Agnes, the newly Papal legate Guy arrived to the country in connection with the refusal to restore the former high duke, and declared the ban over Poland.

Things worsened for Bolesław in 1157, when King Conrad's nephew Frederick Barbarossa, crowned emperor by Pope Adrian IV in 1155, decided to make a new expedition to Poland, thanks to the ongoing pressures by his aunt Agnes, Władysław's wife.

It's unknown why Bolesław opted for a highly security tactics of war, not defending the swampy areas in front of the middle Oder river, which was for centuries the natural defense of Poland, nor the strongholds of Głogów and Bytom in Silesia.

Given the difficult situation, Bolesław was forced to accept the humiliating negotiations and in a shameful[citation needed] ceremony on 30 August 1157, was declared a vassal of the Empire at his camp in Krzyszkowo.

Bolesław formally swore loyalty to the Emperor on Christmas Day in Magdeburg, and gave his younger brother, Casimir II, as a hostage.

Following the defeat by the German forces, Bolesław initiated a bold plan for the conquest of the pagan Prussians, settling beyond the northeastern Polish border along the Baltic coast.

This concept of an early Prussian Crusade was conceived in view of the repeated seizures by more and more Baltic tribes in the several districts of Bolesław's Masovian province.

Casimir was supported in his rebellion by his elder brother Duke Mieszko III the Old of Greater Poland, the magnate Jaksa of Miechów and Sviatoslav, son of Voivode Piotr Włostowic, as well as the Archbishops of Gniezno and Kraków; also, almost all Lesser Polish nobility was on his side.

In 1172 Duke Mieszko III rebelled again; this time supporting his grandnephew Jarosław of Opole (the eldest son of Bolesław I the Tall), who, forced to become a priest in his early years, was barred from the Silesian succession.

Shortly afterwards another rebellion took place, this time of the Lesser Polish nobles, who were extremely dissatisfied with the harsh and dictatorial high duke's government.