The alliance between Bolesław II and Lithuania was strengthened in 1279 when he married Gaudemantė, the daughter of Grand Duke Traidenis, who in her baptism took the name of Sophia.

Part of the local nobility, led by Paweł of Przemankowo, Bishop of Kraków and the Topór family supported the succession of Bolesław II.

However, later in the same year he was expelled from Kraków by the troops of Henryk IV Probus, who gained the decisive favor of the castellan Sulk the Bear (pl: Sułk z Niedźwiedzia), who opened the gates of Wawel Castle to him.

In early February 1289 a coalition of Piast princes (Henry III of Głogów, Przemko of Ścinawa and Bolko I of Opole) organized an expedition to Kraków with the purpose of consolidating the rule of Henryk IV Probus.

For unknown reasons, Bolesław II refused to fight and retreated to his domains in Płock, and in August 1289 Władysław I the Elbow-high was in turn expelled by Henryk IV Probus, who became in the new ruler over Kraków and Sandomierz.

The chosen bride was Princess Kunigunde, sister of King Wenceslaus II of Bohemia; the wedding took place in the first half of 1291.

The following year, after his assassination, Bolesław II supported Władysław I in his brief war against Henry III of Głogów for the succession in Greater Poland.

The hostile policy towards the Kingdom of Bohemia forced[citation needed] Wenceslaus II to launch an attack against Masovia.

In the early 1300s Bolesław II founded the stronghold of Warsaw, contributing to its development in detriment of the nearby Czersk.

[6] In 1279 Bolesław II married firstly to Gaudemantė (baptized as Sophia; d. 1288), a daughter of Grand Duke Traidenis of Lithuania.