Marian Rejewski: Enigma Before Bletchley Park
In December 1932 a 27-year-old mathematician in Warsaw worked out the internal wiring of the German army’s Enigma machine. Marian Rejewski worked at the Polish Cipher Bureau with Jerzy Różycki and Henryk Zygalski. By 1938 Polish intelligence had read about three quarters of the German radio messages it intercepted, and in July 1939 Poland handed its methods and copies of the machine to Britain and France.
Who was Marian Rejewski?
Rejewski was born in Bydgoszcz on 16 August 1905 and died in Warsaw on 13 February 1980. He studied mathematics in Poznań, where in 1929 he was one of the students chosen for a secret cryptology course run with the Polish General Staff’s Cipher Bureau.
What did Rejewski achieve in 1932?
Rejewski used mathematical analysis to reconstruct the wiring of the machine’s rotors, which gave the Cipher Bureau a working basis for attacking messages. The US National Security Agency credits him with the initial analysis that made it possible to read military Enigma.
French intelligence supplied documents obtained from a German agent, which helped the reconstruction.
Różycki, Zygalski and the Polish methods
Różycki and Zygalski developed their own methods, among them Różycki’s clock and Zygalski’s perforated sheets. GCHQ’s historical account describes how the Polish team built replica Enigma machines and mechanised part of the work with the bomba kryptologiczna, or cryptological bomb.
The Polish bomba and the later British Bombe were different machines. GCHQ treats Turing’s exchanges with the Polish cryptanalysts as part of how the British design developed.
The July 1939 meeting that mattered to Britain
On 25 and 26 July 1939, Polish, French and British cryptanalysts met outside Warsaw. GCHQ’s account of the Pyry Forest meeting identifies Alastair Denniston and Dilly Knox as the British representatives. The Polish side revealed how far its Enigma work had progressed.
German changes to Enigma procedures had already cut into Polish success in the months before, and the Poles needed more resources than they had. What they gave away was a head start: the machine’s wiring, their methods and copies of the machine.
In January 1940 Alan Turing travelled to France and met the Polish cryptanalysts, who had been evacuated there. GCHQ describes his conversations with Rejewski as fundamental to the thinking that led to the first British Bombe.
Did Rejewski work at Bletchley Park?
No. From 1939 to 1942 Rejewski worked in France, first in a joint Polish-French team and then, after the fall of France, at the clandestine Cadix centre at Uzès near Nîmes. When the Germans occupied southern France in November 1942, he and Zygalski escaped over the Pyrenees, were imprisoned in Spain, and reached Britain through Portugal and Gibraltar in 1943.
In Britain they were not taken into Bletchley Park. They joined the Polish forces’ radio intelligence company, which moved from Stanmore to a house called The Arches at Felden, near Boxmoor and Hemel Hempstead, in 1943. Rejewski, who started there as a private, worked on simpler German and other ciphers until the end of the war.
Polish units in Britain served under the Polish Commander-in-Chief, not the British Army. Our guide to the Polish government-in-exile explains how they were organised.
After the war
Rejewski returned to Poland on 21 November 1946 and worked as a finance clerk in Bydgoszcz until he retired in 1967. Only then did he write the memoirs, deposited with the Military Historical Institute, that made his part in breaking Enigma known.
Post-war secrecy hid the cooperation for decades. GCHQ has acknowledged that the Polish and French contributions were understated in the first volume of the official history of British intelligence in the Second World War.
Researching a Polish relative’s technical or military service
If a relative served in Polish signals or radio units in Britain, our military research follows that person’s service in the Polish records from the papers the family holds: name, date of birth, service number and unit.
Our guide to Polish service records held by the MOD explains the personnel files, and the Sikorski Institute archive guide covers the London archive of the Polish forces.