He successfully fought in Lithuanian Livonia against Sweden from 1600s to 1617. He took part in the campaign against the Swedes in the Baltic region in 1621–1622 (Polish-Swedish War), where he agreed to a controversial truce (as he had no permission to negotiate it from the king or the Sejm).[2] Important commander of Lithuanian forces during the Smolensk War, where he was instrumental in obtaining the capitulation of the Russian army in the relief of Smolensk.[2] Afterwards, in 1635, he retired from his military career, concentrating on administering his estates. A Calvinist, he was a great protector of Protestants in Lithuania.
He was an opponent of Catholic king Sigismund III Vasa, but a supporter of his more tolerant son, Władysław IV.[2] An advocate of Władysław's marriage to a Protestant princess, he distanced himself from the king after Władysław declined this marriage proposal. He opposed an alliance between the Commonwealth and the Habsburgs. On his lands in Kėdainiai he founded a major Calvinist cultural and religious centre,[2] which flourished till the 19th century as a center of the Lithuanian Reformed Church. His large horse stables were famous throughout Europe.
Collector
Radziwiłł collected various curiosities at the Lubcha Castle: minerals, mollusc shells, corals, hunting trophies, whale bones, elephant tusk, nut shells, and similar items. It is believed that at least three items (moose horn collection, a chair made of horns, and a jaw bone of bowhead whale) of the collection are preserved at the Zoological Museum of Vilnius University.[4]
^Skujienė, Grita (2005). "Istorinė apžvalga"(PDF). In Budrys, Rimantas R. (ed.). Vilniaus universiteto Zoologijos muziejaus paukščių rinkinių aprašymas. Non Passeriformes (in Lithuanian). Vilniaus universiteto leidykla. ISBN9986-19-827-5.