Alan Turing Timeline

Alan Turing 24

1912 Alan Turing born in Maida Vale A father in the Indian Civil Service Alan Mathison Turing is born in London while his parents are on leave from India. He and his brother are largely raised by family friends in Hastings while their father continues his posting. The separation is unremarkable for his class and era and leaves him, by most accounts, self-contained from very early on.
1926 Sherborne School Cycling sixty miles to start term Turing arrives at Sherborne on the first day of the General Strike, cycling around sixty miles from Southampton and staying overnight at an inn rather than miss the start of term. The school, devoted to the classics, finds him a problem: brilliant at mathematics, indifferent to everything else, and untidy about it.
1930 Christopher Morcom dies The friendship that shaped him Turing's closest friend at Sherborne, and the first person to meet him as an intellectual equal, dies of bovine tuberculosis at eighteen. Turing writes to Morcom's mother for years afterwards and turns over, repeatedly and in writing, the question of whether a mind can exist apart from the body that housed it. It is not a large step from there to asking what a mind actually is.
1931 – 1934 King's College, Cambridge Mathematics, and room to be himself Turing reads mathematics at King's, graduating with first-class honours. King's in the 1930s is unusually tolerant, and it is the closest thing to a home he has. He runs long distances, works alone, and reads von Neumann on quantum mechanics.
1935 Elected a Fellow of King's at 22 On the strength of one paper Turing is elected to a fellowship on a dissertation proving the central limit theorem — which, unknown to him, had already been proved a decade earlier. The examiners elect him anyway. An undergraduate rhyme of the time runs that nature and nature's laws were hid in night, and God said let Newton be.
1936 On Computable Numbers The universal machine Answering Hilbert's decision problem, Turing invents an imaginary device — an infinite tape, a read-write head, a table of rules — and shows that some questions cannot be decided by any mechanical procedure whatsoever. To prove it he has to define what a mechanical procedure is, and in doing so describes a single machine that can imitate any other machine given the right instructions. That is a computer. Nobody builds one for another decade.
1938 PhD at Princeton Under Church, alongside von Neumann Turing completes a doctorate at Princeton under Alonzo Church, whose lambda calculus had reached the same conclusion by an entirely different route. He also builds an electric multiplier in the physics department machine shop and starts thinking about cipher machines. Von Neumann offers him a post. He goes home instead.
1939 Reports to Bletchley Park The day after the declaration Turing arrives at Bletchley Park the day after Britain declares war. He is put on naval Enigma, generally reckoned the hardest of the German ciphers and the one others have abandoned as unbreakable. Within months he has redesigned the Polish bomba into something fundamentally different.
1940 The first Bombe Victory The first Bombe, named Victory, is delivered to Bletchley. Turing's insight, refined by Gordon Welchman's diagonal board, is to attack Enigma not by trying keys but by chaining logical contradictions until only consistent settings survive. Over two hundred Bombes are eventually built, and Enigma traffic is read for most of the rest of the war.
1941 Engagement to Joan Clarke Brief, and honest Turing proposes to Joan Clarke, a fellow cryptanalyst in Hut 8 and one of very few women doing the same work at the same level. He tells her almost immediately about his homosexuality, and she is unfazed. He breaks off the engagement some months later, deciding it would not be fair to her. They remain friends.
1941 Naval Enigma broken The Atlantic convoys Hut 8 begins reading German naval Enigma consistently. Convoy routing around U-boat wolfpacks becomes possible, and shipping losses fall sharply. Estimates of how much the war was shortened by Bletchley vary from two to four years, and nobody outside the site knows any of it is happening.
1942 – 1943 Sent to the United States Liaison, and speech encryption Turing crosses the Atlantic to advise American cryptanalysts and to inspect Bell Labs' speech encryption work. He is, at first, refused access to the most sensitive American material. He spends time with Claude Shannon in the Bell Labs cafeteria, where the two discuss whether a machine could be made to think.
1943 – 1945 Delilah A speech scrambler in a shed Back in Britain, Turing builds a portable voice encryption system at Hanslope Park with the engineer Donald Bayley. It works, and is demonstrated by encrypting and recovering a recording of a Churchill speech. The war ends before it is deployed.
1945 – 1947 The ACE at the National Physical Laboratory A stored-program computer, on paper Turing joins the NPL and produces a complete design for the Automatic Computing Engine — the first detailed plan for a stored-program computer, including notions of subroutines and of software as a thing distinct from hardware. Institutional caution and secrecy stall it. Frustrated, he leaves, and a reduced Pilot ACE finally runs in 1950.
1948 Manchester Deputy Director of the Computing Machine Laboratory Max Newman brings Turing to Manchester, where the Baby has just become the first machine to run a stored program. Turing writes the programming manual for the Manchester Mark 1, works on random number generation, and writes one of the earliest chess programs — which he has to execute by hand, taking around half an hour per move, because no machine is fast enough to run it.
1950 Computing Machinery and Intelligence The imitation game Turing opens with "Can machines think?", declares the question meaningless, and replaces it with a test: if a person conversing by teleprinter cannot tell machine from human, the distinction has stopped doing any work. He also anticipates most of the objections that would be raised over the following seventy years and answers them in advance. It remains the founding document of artificial intelligence.
1951 Elected Fellow of the Royal Society For the 1936 paper Turing is elected FRS at thirty-eight, chiefly on the strength of On Computable Numbers. His war work, which is the reason most people who know him think he deserves it, cannot be mentioned.
1952 Convicted of gross indecency For reporting a burglary Turing reports a break-in at his house in Wilmslow. In the course of the investigation he describes his relationship with Arnold Murray plainly to the police, apparently expecting the law to be reformed shortly. He is charged under the same 1885 statute used against Oscar Wilde and, given the choice between prison and probation conditional on hormone treatment, chooses the treatment. He loses his security clearance and is barred from further work at GCHQ.
1952 The Chemical Basis of Morphogenesis Why the leopard has spots While under hormone treatment, Turing publishes on how two chemicals diffusing and reacting at different rates can spontaneously produce stripes, spots and spirals out of a uniform starting state. It explains why biological pattern does not need a blueprint. Largely ignored at the time, it is now foundational in mathematical biology, and the mechanism carries his name.
1954 Alan Turing dies at Wilmslow Cyanide, and a half-eaten apple Turing is found dead at his home at forty-one. The inquest records suicide by cyanide poisoning, and a partly eaten apple beside the bed is never tested. His mother maintained it was an accident from his home chemistry experiments, and some later scholars agree that the evidence does not settle it. He had been under hormone treatment for over a year.
2009 The government apologises Fifty-five years late After a petition gathering tens of thousands of signatures, Prime Minister Gordon Brown issues a formal apology for the treatment Turing received, calling it appalling and acknowledging what the country owed him.
2013 Royal pardon Under the prerogative of mercy Turing receives a posthumous royal pardon on Christmas Eve, following a campaign led in part by scientists and by Justice Minister Chris Grayling's recommendation to the Queen. Critics note that a pardon implies a crime, and that the crime was the law.
2017 The Turing Law Around fifty thousand men Provisions of the Policing and Crime Act come into force, posthumously pardoning all men convicted under the historical laws against homosexual acts and providing a route for the living to have convictions disregarded. It is named after him.
2021 The fifty pound note Issued on his birthday The Bank of England issues a new fifty pound note carrying Turing's portrait, a table from On Computable Numbers, and the line that this is only a foretaste of what is to come. It enters circulation on what would have been his hundred and ninth birthday.