Three mathematicians from Poznań University – Marian Rejewski, Henryk Zygalski and Jerzy Rozycki – recruited to the Polish Cipher Bureau in the 1920s, were the first to break the Enigma machine. This machine had originally been developed after the First World War for commercial use and was openly available for sale. However, it had no plugboard. This was added in the inter-war years after the German military took over its use and gave the machine the phenomenal 158 million million million possible settings. By some clever mathematics the Poles deduced the wiring of the five common wheels. Among devices developed by the trio was a ‘bomba’ an electro-mechanical machine which found Enigma settings, utilising the much simpler indicator system in use at that time, but it was nothing like the Turing-Welchman Bombe. The outstanding achievement of the Polish team, and the vital information they supplied to Britain and France on the eve of the war led the way to the British successes which played such a vital role in the secret codebreaking activities at Bletchley Park.