Chronology of events

1884 23 July	Alfred Dillwyn Knox born in Oxford.
1884	Dilly’s father, Edmund Arbuthnott Knox, leaves Merton College to take up living at Kibworth in Leicestershire.
1891	Father moves to Aston, Birmingham, as Bishop Sufragan of Coventry.
1895	Dilly sent to Summer Fields preparatory school in Oxford.
1896	First in election to Eton.
1903	Father becomes Bishop of Manchester.
1903	Dilly becomes a scholar at King’s College, Cambridge, reading classics. Heavily influenced by Walter Headlam.
1907	Leaves Cambridge. Teaches classics and ancient history at St Paul’s.
1909	Fellow of King’s College, Cambridge. Begins work on completing Headlam’s Herodas. Commutes from Cambridge to British Museum to work on papyri.
1914	Outbreak of war. Tries to enlist as military dispatch rider but eyesight fails him.
1915	Dilly joins Admiralty’s Room 40 codebreaking section.
1917	Breaks U-boat code. Commissioned as lieutenant in the Royal Naval Volunteer Reserve.
1919	Decides to continue as a codebreaker through peacetime in the newly formed Government Code & Cypher School (GC&CS).
1920	Marries his Room 40 secretary Olive Roddam.
1921	Moves to Courns Wood, near High Wycombe, Buckinghamshire.
1922	GC&CS placed under Foreign Office. Dilly works on diplomatic messages.
1922	Publishes the Headlam/Knox Herodas.
1923	Offered professorship of Greek at Leeds University as result of dissertation on Cercidas and his work on Herodas.
1923	Arthur Scherbius markets a new electro-mechanical cipher machine which he calls Enigma.
1925	GC&CS moves to share offices with Secret Intelligence Service (SIS) at Broadway Buildings. Dilly said to acquire an Enigma in Vienna for his own use.
1926	Dilly works with John Tiltman to break messages passed by clandestine network of Comintern agents. Codebreaking operation is codenamed Mask.
1928	GC&CS acquires a commercial Enigma machine.
1929	Dilly publishes new translation of Herodas for Loeb Classical Library edition.
1929	Hugh Foss breaks commercial Enigma machine as part of GC&CS test of its security for possible use by British government. Deems it too insecure.
1930	Germany adds plugboard to commercial machine, significantly enhancing its security. Dilly and Tiltman continue to concentrate on Comintern and Soviet codes and there is little interception of German messages.
1931	Gustave Bertrand obtains German spy ‘pinches’ of material from a French agent inside the German war ministry codenamed Asché. Bertrand offers more documents but demands payment. Offer not taken up but photographs taken during assessment of material reveal the addition of the plugboard.
1931	Offer of Bertrand’s Asché ‘pinches’, including daily army machine settings, eagerly accepted by Poles.
1932	Polish codebreaker Marian Rejewski breaks the Enigma machine theoretically using permutation theory.
1933	Poles begin reading German Enigma messages. Hitler comes to power and begins building up the German armed forces.
1935	Mussolini’s Italy invades Abyssinia. Joint Anglo-French wireless intercept station set up in southern France.
1936	Germany sells commercial Enigma machine to Italy and Spain. German plugboard Enigma messages intercepted when German navy carries out manoeuvres in the Mediterranean.
1937	Dilly uses his own ‘rodding’ techniques to break the wiring on the wheels of the ‘K’ model commercial machine used by Italy in the Spanish Civil War. Wilfred Bodsworth, another GC&CS codebreaker, uses Dilly’s ‘rodding’ techniques to break the Enigma machine used by the Spanish naval attaché. Dilly turns his attention to breaking German army and air force messages through their indicators.
1938 March	Germany annexes Austria. Admiral Hugh Sinclair, the SIS Chief, buys Bletchley Park as a ‘war station’ for both SIS and GC&CS.
August	Codebreakers make practice visit to Bletchley under cover of ‘Captain Ridley’s Shooting Party’.
November	Bertrand is invited to meet codebreakers and hands over spy ‘pinches’, known here as ‘Scarlet Pimpernels.’ These include an operator’s manual which gives ninety letters of clear text and its enciphered equivalent together with the key setting. Dilly now only needs to know the diagonal, the order in which the machine’s typewriter keys are connected to the entry plate to break the German army and air force Enigma. The diagonal on the commercial machines followed the keyboard and so was called the QWERTZU by Dilly.
1939 January	Meeting between the British, Polish and French codebreakers in Paris produces nothing new for the British.
1939 July	Meeting in Pyry Forest just outside Warsaw tells Dilly what he needs to know. The diagonal was not QWERTZU as in the commercial machines but ABCDE, such a simple order that the British codebreakers had dismissed it without even testing it. Dilly sends the information back to GC&CS and the wheel wiring is broken within two hours. By now he has been diagnosed with lymphatic cancer.
1939 August	GC&CS moves to Bletchley Park ‘war station’. Dilly put in charge of research section in the Cottage, assisted by Tony Kendrick, John Jeffreys, Alan Turing, Peter Twinn, Gordon Welchman and three female clerks. Sets up workshop in the stable-yard, where engineers work with Turing on experimental electro-mechanical codebreaking, which leads to the creation of the bombe.
1940 January	First current German Enigma message broken in Cottage. Dilly invents ‘cillis’ to speed up codebreaking process and solves weather codes which give away daily plugboard settings. Success of Turing’s bombe turns Bletchley Park into a production line, leaving Dilly feeling sidelined. In March, he is given a new Enigma research section in the now enlarged Cottage and sets to work breaking the machines no one else can manage.
1940	German railway Enigma broken by Hut 8 using Dilly’s methods. Turing’s Treatise on Enigma explains Dilly’s methodology to newcomers.
1940 September	Italian navy Enigma messages broken.
1941 March	Cottage breaks details of Italian navy plans for Battle of Matapan, leading to British success.
1941 October	Dilly breaks Abwehr multi-turnover ‘Lobster’ Enigma, allowing SIS to monitor German secret service messages. This is vital to the Double Cross system of captured German agents used by MI5 and SIS to feed false information to the German high command about allied intentions during the invasions of north Africa and Italy and most particularly for the D-Day Normandy landings.
1942	Dilly’s team, now known as Intelligence Services Knox (ISK), breaks the Abwehr GGG machine used for communications with Spain. Dilly is now so ill that he is only able to work from home. Twinn takes over temporarily as head of section, but Dilly is still very much at work behind the scenes.
1943 27 February	Dilly dies at home, aged fifty-eight, having been given the CMG on his deathbed by an emissary from the Palace. He sends the decoration to his ISK section, saying that it was really earned by them.