1642
Calculating machine invented by Blaise Pascal, a 19-year-old Frenchman. It is never built.
1693
Another, similar machine designed by the German Gottfried Leibniz.
1801
French textile manufacturer Jacques Jacquard invents ‘operation cards,’ an ancestor of the computer programme.
1821
Charles Babbage, a Cambridge mathematics professor, invents the ‘difference engine’ – a series of calculating machines connected to work in unison, and based on Leibniz’ principles.
1834
Analytical engine also developed by Babbage. This is the fundamental concept of a computer with a programme and memory.
1890s
American Herman Hollerith uses Jacquard’s card system to automate the analysis of US census returns. He later founds IBM. Bazeries enciphering machine is invented by a French army officer. Enciphering machines equipped with keyboards.
1914
British Naval Intelligence begins intercepting German signals traffic, establishing Britain’s most efficient decrypting service of World War I. Its greatest triumph, in 1917, is the interception of the ‘Zimmerman Telegram’ from Germany’s Foreign Minister to her ambassador in Mexico, offering incentives for Mexican alliance with the Central Powers. This causes widespread anti-German feeling in the US.
1918
Enigma invented in Germany for use in banks and other businesses.
1921
Washington Naval Conference. Japan is persuaded by the US and Britain to maintain a navy smaller than theirs. Anglo-American negotiators take a firm stance because decryption of a diplomatic message has shown Japan willing to compromise.
1923
Enigma displayed at the International Postal Union’s congress in Berne.
1926
German Navy begins to use Enigma, followed by German Army in 1928.
1929
Polish Intelligence begins analysis of Enigma after a machine is accidentally sent to Warsaw from Germany. US ‘Black Chamber’ – decrypting department – closed down. Yardley, the American decrypter of the Japanese telegram in 1921, writes a book, The American Black Chamber, about his experiences. It causes outrage in Japan and leads to the building of a powerful fleet. In 1934 Japan withdraws from the 1921 Naval Agreement.
1930
Japanese Government begins using Enigma.
1931
Japanese invasion of Manchuria, the unofficial beginning of World War II.
1932
Hans Thilo Schmidt, a German civil servant, begins selling Enigma secrets to France.
1933
Forschungsamt, or Research Office, established in Germany as signals intelligence unit, and attached to Luftwaffe.Polish cryptographer Marian Rejewski discovers the wiring layout for Enigma.
1936
German operators begin changing Enigma’s wheel-order monthly, then daily. Z1 computer designed and built in Berlin by Konrad Zuse. It is followed by the Z2 and Z3. The latter is believed to be the first electronic computer ever built.
1937
Polish mechanic with experience of work in a German Enigma factory is smuggled to France to build a replica.
December
Large-scale Japanese invasion of China.
1938
Bletchley Park, Bedfordshire, is bought by a mysterious naval officer and work begins on the relocation of the Government Code and Cipher School.
September
Munich Agreement. Britain and France allow Germany to occupy and dismember Czechoslovakia.
1939
August
Hitler-Stalin pact divides Poland.
September
Hitler invades Poland. Britain and France declare war on Germany.
October
Sinking of HMS Royal Oak in Scapa Flow by Gunther Prien.
1940
March
The first of Turing’s Bombes becomes operational at Bletchley.
April/May
‘Phoney War’ ends with German invasion of Scandinavia and Western Europe. Winston Churchill, a keen supporter of the work at Bletchley Park, becomes Prime Minister and Britain’s war leader.
August
Battle of Britain. German Luftwaffe attempts to destroy numerically inferior RAF. Radar, and Enigma, warn defenders of enemy strength and intentions, making possible effective, and successful response. ‘Blitz’ – intensive bombing campaign against British cities, begins and lasts throughout winter.
1941
US Intelligence breaks Japanese cipher.
March
Battle of Cape Matapan.
May
German trawler Munchen captured with Enigma settings on board. U-110 boarded in Atlantic. Vital codebooks and equipment seized.
June
Bismarck sunk.
June
Hitler’s forces invade Russia, bringing the Soviet Union into the conflict on the side of the Allies.
December
Japanese attack on Pearl Harbor brings about war between the United States and Japan. Hitler declares war on America.
1942
January
Germans break US military cipher in Cairo and obtain detailed knowledge of Allied plans.
February
Japanese capture Singapore, a key stage in their rapid conquest of much of East Asia.
June
Battles of Leyte Gulf and Midway. US Navy defeats enemy carrier-force and ends Japanese dominance of the Pacific.
August
US landings on Guadalcanal begin the slow and costly task of driving enemy forces from islands and territories throughout the Pacific.
October
Battle at El Alamein, Egypt, ends Axis hopes of conquering North Africa.
November
Operation Torch, Allied landings in North Africa.
1943
Extremely heavy U-boat losses (47 boats) convince Admiral Donitz that the Battle of the Atlantic cannot be won. Submarine fleet withdrawn from north Atlantic.
January
Surrounded German 6th Army surrenders at Stalingrad. Its defeat signals turning-point in the war against Hitler.
February
Chindits, commanded by Orde Wingate, become operational in Burma.
April
Ambush and killing of Admiral Yamamoto after decrypted messages reveal the time and route of a plane journey he is making over the Pacific.
July
Allied landings in Sicily. The arrival of enemy forces on Italian soil leads to the dismissal of Mussolini, the forming of a new Government and, in September, the surrender of Italy, which then joins the Allies.
1944
Development of ‘Colossus,’ the world’s first programmable computer, at Bletchley.
January
Hitler’s ‘V weapons’ – guided missiles – begin a second Blitz on England.
June
Allied invasion of Normandy brings the war onto the European mainland.
July
Plot to assassinate Hitler by senior officers. Among those imprisoned in subseuent retaliation is Admiral Canaris, former head of the Abwehr, the German secret service. He is executed in early
1945.
August
Allied landings in south of France.
December
Ardennes offensive. German forces make spirited attack in Belgium and Luxembourg, taking by surprise Allied forces whose decrypters had failed to notice that this action was imminent.
1945
January
Death in captivity of Noor Inayat Khan, SOE agent.
March
Allied forces cross the Rhine.
European war ends in May after suicide of Hitler the previous month. War against Japan ends in August following the dropping of atomic bombs on Hiroshima and Nagasaki.