During the interwar period (1918-1939), Poznań was the country’s main Germanic studies centre and the power base of the Polish Western Union – and a city where intelligence operatives from both sides were hard at work. This is also where the German “Enigma” encryption machine had its code broken. This device, which resembled a typewriter, was invented in the 1920s. It was in regular use by the German armed forces and German experts deemed the “Enigma” code to be unbreakable. Overcoming this barrier required a comprehensive knowledge of mathematics, tremendous cryptographic skills and a consummate knowledge of the German language.

About 20 advanced mathematics students, for whom a special, classified cryptology course had been created, fulfilled these conditions. This was conducted in the Faculty of Mathematics at the University of Poznań in the basement of the former Imperial Palace in ul. Św. Marcin. The three brightest, Marian Rejewski, Jerzy Różycki and Henryk Zygalski, were removed from the group and employed by the Polish Military Intelligence Code Department (BS-4) in 1932. The code was broken after four months. Poland’s allies soon received replicas of the German device. This was later to be of enormous significance on the western front during WWII. The team was later employed by British Intelligence as expert cryptologists.

The young cryptologists are remembered by a monument erected in front of Poznań’s Imperial Palace in 2007.