As a result of the defeat following the Invasion of Poland by Nazi Germany in 1939, Piłsudski was forced to flee, but was arrested by the Soviet NKVD in Vilnius (Wilno). He was freed as a result of a prisoner exchange in 1941, and went to the United Kingdom where he died in exile in 1950 in Penley. He is buried in Wrexham, North East Wales, United Kingdom.