Marian Adam Rejewski [ˈmarjan reˈjefski] (16 August 1905 – 13 February 1980) was a Polish mathematician and cryptologist who reconstructed the Nazi German military Enigma cipher machine sight-unseen in 1932. The cryptologic achievements of Rejewski and colleagues Jerzy Różycki and Henryk Zygalski enabled the British to begin reading German Enigma-encrypted messages at the start of World War II, seven years after Rejewski's original reconstruction of the machine.