Bolesław's mother, Maria Dobroniega of Kiev, held familial ties to the influential Kievan prince Yaroslav the Wise, which further enriched his connections to powerful Eastern European dynasties.

If you do not do so, we will burn down Kiev Castle before it falls into the hands of the Poles, while we ourselves, knowing our possessions, children and families, will go overseas to Greece to escape the yoke of the angry enemy.From princes Sviatoslav and Vseslav, the Kievans receive a kind reply that they will send envoys to Prince Iziaslav and ask him to refrain from hostile moves with the Polish army and to peacefully enter their country in order to take back all their possessions.

When these met him near Kiev, they addressed him and the Polish King Bolesław on behalf of the princes Sviatoslav and Vseslav with the following words:[4]: 113 In vain, you brought such a strong army to such distant lands.

Upon arrival, the perpetrators and leaders of the conspiracy, seventy in number, were partially blinded, some murdered and took cruel revenge, losing even those who pretended to be innocent.

But when Mstislav reported that there was complete security and calm among the inhabitants, and that King Bolesław of Poland had arrived with Prince Iziaslav, the Kievans first came out to meet him seven miles away, and then welcomed him, offering magnificent gifts.

[8][3] However, his pride and arrogance, evident in his interaction with Prince Iziaslav, also revealed his vulnerabilities, which he accomplished by sitting on a horse while lumbering his relative by the beard.

[4]: 115  Acknowledged along with his army by Prince Izasław with lavish gifts, Bolesław proceeded towards Przemyśl, seizing various fortifications and strongholds along the San River, some through cooperation, others by coercion.

Learning that Przemyśl sheltered many Ruthenian people seeking refuge from neighboring fortresses and villages, Bolesław resolved to launch a full-scale assault.

[4]: 115 Przemyśl, a sizable city teeming with inhabitants and newcomers, fortified with deep trenches, high walls, and guarded by the San River from the north, posed a formidable challenge.

Hindered temporarily by the swollen San River caused by heavy rains, Bolesław eventually crossed with his troops and established a camp near the city.

[4]: 116 Exploiting opportunities, he dispatched soldiers to harass enemy fields, prompting the foes to retreat to forests and marshes, some too intimidated to venture beyond their fortified positions.

Despite skirmishes yielding no decisive outcome, a significant counterattack compelled a Ruthenian retreat back to Przemyśl, where panic ensued, allowing the Polish forces to capture or disarm many foes.

[4]: 117  After providing time for rest and tending to the wounded, he fortified the city and maintained the siege despite the challenges posed by its strategic location and formidable defenses.

[6][10] In addition, rumors of Bolesław's controversial personal life, including alleged affairs with married women, further complicated his legacy and the succession crisis that followed his death.