Following the Swedish retreat and Polish resurgence, Bogusław Radziwiłł chose exile in Brandenburg-Prussia, with his mother's family.

Her guardianship was entrusted to her father's cousin and host (and her future father-in-law) Frederick William, Elector of Brandenburg.

Radziwiłł financed the issue of the catechism and primer in the Lithuanian language, Pradzia pamoksla del mazu Weykialu…, which was printed in Königsberg in 1680.

[1][clarification needed] Radziwiłł first married Margrave Louis of Brandenburg (1666-1687), the youngest son of Frederick William the Great Elector and Princess Louise Henriette of Orange-Nassau, at Königsberg Castle on 7 January 1681 at the age of thirteen.

Of their four children, only the youngest daughter, Countess Palatine Elizabeth Augusta Sophie of Neuburg survived childhood.

Radziwiłł remarried in Berlin on 10 August 1688 to the future Charles III Philip, Elector Palatine, brother-in-law of Leopold I, Holy Roman Emperor.