Prince Krzysztof Radziwill (Christopher Radvila, Lithuanian: Kristupas Radvila) (22 March 1585, Biržai – 19 November 1640) was a Polish-Lithuanian noble (szlachcic), and a notable magnate, politician and military commander of his epoch.
Sometimes referred to as Krzysztof Radziwill II, to distinguish him from his father, Krzysztof Mikolaj 'Piorun' Radziwll.
A proud magnate, sensitive to the point of ancestral honour and heritage, convinced of his vocation to play a leading role in the country.
He was a successful military leader, but selfishness and pride divided his supporters and weakened his significance in the politics.
As the leader of the Lithuanian Calvinists, he was often threatened and disliked by the zealous and ultra-Catholic King of Poland, Sigismund III Vasa.