The road to Bletchley Park

2. Origins of Enigma

   1918 — Enigma is patented

   Arthur Scherbius patents a rotor-based cipher machine he calls Enigma.

3. Origins of Enigma

   1926 — The German navy adopts Enigma

   The Kriegsmarine becomes the first branch of the German military to use Enigma.

4. Origins of Enigma

   1931 — A spy shares documents

   Hans-Thilo Schmidt sells Enigma manuals to French intelligence.

5. Origins of Enigma

   1932 — Poland breaks Enigma

   Marian Rejewski reconstructs the Enigma wiring using mathematics and the spy documents.

6. Origins of Enigma

   1938 — The bomba

   Poland builds the bomba, an electromechanical device that tests Enigma rotor positions automatically.

7. Origins of Enigma

   Jul 1939 — The Warsaw meeting

   Poland shares everything with Britain and France, just weeks before war breaks out.

8. Bletchley Park

   Aug 1939 — Station X opens

   The Government Code and Cypher School moves to Bletchley Park in Buckinghamshire.

9. Bletchley Park

   Sep 1939 — War begins; Turing arrives

   Alan Turing joins GC&CS and begins work on a faster, more powerful Bombe.

10. Breakthroughs

    1940 — The first Turing-Welchman Bombes

    Gordon Welchman adds the diagonal board, making the Bombe far more effective.

11. Breakthroughs

    1941 — The U-110 capture

    Key documents from a German U-boat help break Naval Enigma.

12. Breakthroughs

    1942 — The Atlantic blackout

    Germany adds a fourth rotor to U-boat Enigma, plunging Hut 8 into a months-long blackout.

13. Breakthroughs

    1943 — Colossus

    The world's first programmable electronic computer is built to attack the Lorenz cipher.

14. Breakthroughs

    1944 — Ultra and D-Day

    Decoded Enigma and Lorenz messages help confirm German reactions to the Normandy landings.

15. Aftermath

    1945 — Victory and silence

    The war ends; Bletchley Park's work is kept secret for decades.

Codebreaking at Bletchley Park was not a single flash of genius. It was a chain of discoveries — Polish mathematics, French espionage, British engineering, captured documents, and thousands of people working in secret. Each event on this timeline made the next one possible, and together they turned an 'unbreakable' cipher into one of the most important intelligence victories of the war.