
Bogusław Radziwiłł (3 May 1620-31 December 1669) was a Lithuanian princely magnate, an Imperial Prince of the Holy Roman Empire, and Grand Hetman of Swedish Lithuania from 1655 to 1657.
Biography[]
Bogusław Radziwiłł was born in Gdansk, Poland-Lithuania in 1620, a scion of the mightiest family of the Grand Duchy of Lithuania and the cousin of Janusz Radziwiłł. Bogusław studied in Germany, the Netherlands, England, and France from 1637 to 1648 before joining his cousin Janusz Radziwiłł in backing King Charles X Gustav of Sweden's invasion of Poland in 1655. The Radziwiłłs were allowed to rule over two duchies within Swedish Lithuania in exchange for their support.

Radziwiłł at the Battle of Prostki, 1656
The Swedish defeat and eventual retreat from Poland ended the Radziwiłłs' plans. Janusz died at Tykocin Castle in December 1655, and Bogusław Radziwiłł and his forces retreated to Prussia. Bogusław was defeated and captured at the Battle of Prostki on 8 October 1656, and he was briefly enslaved by the Tatars before being handed over to the Poles. He married the late Janusz's daughter and became Governor of Brandenburg-Prussia in 1657, and he died in exile in Konigsberg in 1669.