In the 1930s, Hitler’s Nazi regime came to power in Germany. As the years passed, the military might of Germany shocked most of Europe with technological marvels they’d never seen before.

German troops were on the move almost daily, keeping tensions high as the whole of Europe watched on — helpless to stop Germany’s military might.

The British Prime Minister, Neville Chamberlain, made a last-ditch effort to slow down the Nazi’s aggression while avoiding war when he met with Hitler in Munich on September 30th, 1938. But no one expected this to work.

A war seemed inevitable, and with the Nazi’s military power no one knew what the outcome would be. The only thing they knew was it’d be the worst war humankind had ever seen.

The British government knew they’d need to take an innovative approach to winning this war. Little did they know that Britain’s eventual victory could be attributed largely to one man.

Turing’s early days

2014’s The Imitation Game tells the story of Alan Turing, who is played by Benedict Cumberbatch in the movie.

Turing was born on June 23rd, 1912 in London, England to an upper-middle-class family. He started school at the age of six, and right away his teachers knew there was something different about him.

As he grew, so did Turing’s love for school. In 1926, Turing’s first day of school at Sherborne in Dorset happened to coincide with the 1926 General Strike — an event where over 1.7 million workers went on strike. So determined not to miss his first day, Turing rode his bicycle from his home in Southampton —  over 60 miles — by himself just to make sure he’d get to school on time.

At only 15 years old, Turing found the work of Albert Einstein and for the first time was able to develop Einstein’s work. He showed true genius when he came to conclusions from Einstein’s work that Einstein never made clear in the work itself.

Despite his brilliant mind, many of Turing’s professors didn’t like how utterly focused Turing

was math and science. In Andrew Hodges book entitled, Alan Turing: The Enigma, he quotes one of the letters that Turing’s teachers sent to his parents:

“I hope he will not fall between two stools. If he is to stay at public school, he must aim at becoming educated. If he is to be solely a Scientific Specialist, he is wasting his time at a public school.”

While in school in Sherborne, which is on the southern coast of England, Turing drew a ton of inspiration from many of the greatest mathematicians of the time – names like Sir Arthur Eddington, John von Neumann, Max Newman and Bertrand Russell.

At Sherborne, Turing became close friends with a boy by the name of Christopher Morcom. The two struck up quite a friendship and many historians today refer to Marcom as Turing’s first love. The two decided to apply to King’s College together.

Unfortunately, Morcom contracted tuberculosis in February of 1930 after drinking some infected cow’s milk. He died suddenly, leaving Turing stricken with grief.

In The Imitation Game, Benedict Cumberbatch plays Turing as a very shy, socially awkward person. And this is actually quite true. Although he was impressing everyone around him with his brilliance, Turing didn’t have many friends.

So when Morcom died, Turing threw himself into the only thing he could — his studies.

A growing appreciation for problem-solving

In 1931, Turing learned of the “Decision Problem” by German mathematician David Hilbert. The problem, essentially, was that mathematics of the day were prone to paradoxes and inconsistencies. So Hilbert proposed a solution to this, securing a foundation for all mathematics.

Later the same year, another German mathematician by the name of Kurt Godel published a paper which proved two key things for any computable, axiomatic system that’s powerful enough to describe arithmetic. First, if the system is consistent, it can’t be complete. Secondly, the consistency of any reasoning can’t be proven in the system.

This fascinated Turing.

By the age of 23, Turing excelled so much in his studies he was given the highest award that can be given to an individual at King’s College — the Fellowship of King’s College — also referred to as being a Fellow.

Between being named a Fellow of King’s College and before his next step, Turing spent almost a year on Hilbert’s Decision Problem. His solution was something that’d change modern computing forever — the Turing machine.

The Turing machine was more of a theoretical machine in that it wasn’t ever intended to be built. However, the importance lay in the fact that it could be implemented.

Otherwise, it’d just be science fiction.

Essentially a Turing machine has tables of programmed behavior that’s complex enough to read the tables of other Turing machines. Then, the first Turing machine would be able to do what another machine could do. It’s a bit of an abstract concept, but it’s an important one because it’s essentially the same concept that’s the backbone of today’s computers.

So if you have the Turing machine that’s sort of like a computer program, you’d need a computer to run it on. This is what Turing called a universal machine. The correlation between these two is similar to the correlation between today’s computer hardware and the software that runs on it.

Let’s say you have Microsoft Word on your computer. You want to be able to edit a photo, but Word can’t really do that. However, what you can do is install Photoshop to edit your photo and then put that photo into Word. This is happening with software programs but it’s on a single device — your computer.

While this seems simple in today’s computing world, you have to remember that in 1936 computers like we have today simply didn’t exist.

Although it garnered the name ‘machine’, think of the Turing machine more like a modern-day software program. A universal machine could run an infinite number of subset machines that could essentially talk to each other to accomplish whatever you need. The universal machine, your computer, can have multiple subsets of machines — or software — installed to do what you want.

In this way, Turing concluded that it if anything is computable, it can be computed by this one machine: a universal Turing machine.

The truth behind the machine named ‘Christopher’

He presented this work to Max Newman in April 1936, and this opened up a whole new world of thought.

As it happened, a mathematician at Princeton named Alonzo Church had been working on similar solutions, and so it was that, after graduating from King’s College with a special distinction, Turing left England for the United States where he attended Princeton University to study mathematics further under Church.

Just to add some context to this, Turing started studying at Princeton in September of 1936. In June of 1938, he got a Ph.D. from Princeton with a dissertation entitled, Systems of Logic Based on Ordinals, where he introduced the concept of ordinal logic and the idea of relative computing.

After graduating from Princeton, he returned to England where he was almost immediately recruited by the Government Codes and Ciphers School.

On September 9th, 1939, England declared war on Germany. The next day, Turing arrived at Bletchley Park to start working on his machine for a new purpose — as a device for decrypting the messages sent by Germans using their Enigma machines.

In The Imitation Game, Benedict Cumberbatch’s version of Turing names his machine ‘Christopher’, after his first love.

In reality, this machine was called Bombe.

It was later renamed “Victory”, but it was called Bombe because it was based on an earlier decryption device the Polish built called the Bomba Kryptlogiczna. That’s Polish for Cryptologic Bomb, and they actually had some success in cracking the Enigma cipher.

The Polish, certainly knowing that their time was limited, sent as much as they could to help British Intelligence. They sent Enigma machines they had captured and the basic frameworks for their own Bombe machines. These were critical to helping Turing and his team.

Then, in 1939, Germany invaded Poland. From here, it would seem British Intelligence was on its own.

World War II in full swing

Why is the German Enigma so important to break? Well, the movie did a good job of explaining the importance, but let’s break it down.

As the Nazi’s started to expand their empire across Europe, they knew one of the keys to success was being able to keep their plans away from the enemy.

To do this, their scientists built an incredible piece of technology. The German Enigma machines were used to create a cipher — a code — that could only be read by another Enigma machine using a special decryption key. And that key was frequently changed.

Think of it sort of like having two-factor authentication today. With today’s two-factor authentication you have your normal username and password, but then when you log into a website, it’ll ask you for a unique code. That code is generated with a second device — usually your smartphone. And this code changes, usually every 30 seconds. The end result is basically you need to have your phone handy to be able to login…this makes it next to impossible for someone to get into your account without your phone.

While the Enigma machine obviously didn’t run from a smartphone, the basic concept was similar. Having access to an Enigma machine itself isn’t any good if you don’t know the decryption code. And the Germans randomly changed the code, so to break the Enigma code you need the machine, of course, but you also need to know what the random code is.

Simply put — it was next to impossible to hack an Enigma machine. The Nazi’s knew this, and because of this, they used Enigma to transmit all sorts of top secret information. On the flip side, if the British Intelligence could crack Enigma, all of a sudden every German surprise attack on land and sea, not to mention countless other surprises that the Germans threw at the allies, would no longer be secret.

Breaking the Enigma

In 1938, as the Nazi’s were just starting their bloody trail across Europe, British Intelligence set up Bletchley Park and gathered all of the brightest minds with the sole purpose of decrypting German ciphers — most predominantly the Enigma cipher.

Bletchley Park is located in southeastern England, and they actually have a working version of Bombe there today. If you get the chance to visit, I’d highly recommend it!

In The Imitation Game, they emphasized the tension between Turing and his military superiors as England’s position in the war grew increasingly dire and Turing’s machine had yet to break the Enigma code.

While the basics of this are correct, in truth the Enigma had to be broken more than once. This was because the German Army and Air Force used a different Enigma system than the Navy. In fact, the Polish’s Bombe made significant headway in breaking the Enigma ciphers for the German Army and Air Force.

Turing and his team may have based their work on the Polish Bombe, but they made significant improvements to it and, on March 18th, 1940, the first Bombe was installed at Bletchley Park.

To give a sense of scale for these machines, each Bombe was about 7 feet wide, 6 and a half feet tall, 2 feet deep and weighed one ton.

There were two primary things that the British Bombe needed to be successful in breaking an Enigma-encrypted message. First, they needed to know the Enigma hardware itself. Capturing the Enigma hardware became a priority for the allies and had actually spawned movies of its own, such as U-571. The other thing they needed for the Bombe to be able to break the encryption, was to be able to guess at least 20 letters from the text.

That’s where, in the movie, they were able to break the code because of guessing the words “Heil Hitler” and “weather” were in the encryption. While not always from weather reports, the German’s use of Heil Hitler in their communications did make for this to be a common method of breaking the code.

Unlike in the movie where they make it seem as if Turing himself built the machine, the first Bombe was actually built by the British Tabulating Machine Company at Letchworth — about 30 miles from Bletchley Park.

Another differentiator from the movie and real life came when, in the movie, Turing went directly to Winston Churchill for funding for his first Bombe. That’s not quite how it happened. Although, the cost of 100,000 pounds mentioned in the movie was correct.

That’s about $6.5 million in today’s United States dollars.

Despite the success of breaking the ciphers using the expensive, but effective, Bombe machine, there was simply too much for their limited team to handle.

Imagine, if you will, that you have a single computer trying to monitor the traffic of an entire world war. Even with the computing power of a modern-day system, that’d be quite a difficult task.

Not only that but even though Turing’s team was able to crack the German code, it wasn’t like they knew which communications were which before decrypting them. So one message might be something as simple as the weather, another one might be something important. There’s no way to tell before it’s decrypted — at which point you’ve already spent the time to decrypt it.

So it’s completely understandable when Turing and his team started to get frustrated. They felt as if their work just wasn’t enough.

Despite this feeling, they were making quite a huge difference and had significantly decreased the amount of losses the English suffered.

On August 8th, 1940, a second Bombe was installed. But it still wasn’t enough to turn the tide of the war.

Growing increasingly fed up with the lack of response as he was trying to get more people and funding for more Bombes to help decrypt everything that was coming through, that’s when Turing wrote a letter directly to Churchill.

Andrew Hodges’ biography of Turing has the text of the memo from Churchill. It was written to General Hastings Ismay, who was Churchill’s chief military assistant:

“ACTION THIS DAY. Make sure they have all they want on extreme priority and report to me that this has been done.”

Churchill’s response was like magic — all of a sudden, Turing had whatever he needed. By the end of the war, over 200 Bombes were in operation.

With very accurate results, the British Bombes were able to break the encryption for the Army and Air Force Enigma machines because they used three rotors.

Breaking the unbreakable code

The German Navy, however, had more rotors on their Enigma machines, so this made it a lot more difficult. Throughout the war, Germany kept changing their Enigma machines.

This was another reason why the allies had to keep capturing updated Enigma hardware. The Navy’s rotors started with twice as many as the Army and Air Force at six, then it was updated to have seven and finally, by the end of the war, there were eight rotors.

At the end of 1939, Turing had solved the additional complexity for the Navy’s Enigma — at least, in theory. Taking this theory to practice would prove to be more difficult.

To test his theories, Turing invented a new method of ruling out certain sequences of the Enigma rotors. This significantly decreased how long it took to test the Bombe machine’s settings and, by extension, got them up and running much faster.

In The Imitation Game, playing the role of Joan Clarke is Kiera Knightly. In the movie, Clarke worked in Hut 3 with the other women, but in truth, Clarke worked in Hut 8 alongside Turing.

The two formed a great friendship, as they did in the movie. In the movie, Knightly’s character complains that her parents are pressuring her to get married. Since homosexuality for men — but not women — was illegal at the time, the arrangement in the movie makes sense.

While there’s no proof of this being the rationale, we know that Clarke introduced Turing to her family shortly after Turing proposed to her in 1941.

The engagement was short-lived, though, when Turing admitted his homosexuality to Clarke and while Clarke didn’t really seem to care — she’s been reported as being “unfazed” by it — it was ultimately Turing who decided to break off the engagement.

After years of working on breaking the German Navy’s more complex Enigma, Turing finally broke it in 1942.

Turing travels to the United States

Although the British had been in the war for years now, they had a new ally across the ocean in the United States, who joined the war after Pearl Harbor on December 7th, 1941.

As part of intelligence sharing between England and their new allies, Turing traveled to the US where he helped the US Navy build American Bombes. While in the U.S., he visited Washington as well as the US Navy’s lab in Dayton, Ohio.

Although he wasn’t too fond of the way the Americans were building their Bombes, saying they relied too much on machinery instead of thought, he shared what he knew about the German Enigma machines with the Americans. In exchange, he was given access to the encryption system being set up for private conversations between Churchill and Roosevelt.

He was essentially Churchill’s verification that the system would be secure.

Turing returned to Bletchley Park in 1943, where he continued with decryption efforts. On September 2nd, 1945, the Japanese signed an unconditional surrender — ending World War II.

Just like in The Imitation Game, keeping the work at Bletchley Park secret was of utmost importance. Because of this, it wasn’t until a British Royal Air Force officer by the name of F.W. Winterbotham published his book, The Ultra Secret, that the public really started to understand the work that went on there.

Although he couldn’t use, or even talk about, the work he’d done at Bletchley Park, after the war Turing left the British Intelligence and went to work at the National Physical Laboratory (NPL) in London where he started working on a machine that’d rival everything he’d built so far.

Building the modern computer

In 1946, Alan Turing finished a proposal for an electronic digital stored-program computing machine called the Automatic Computing Engine (ACE).

While a great theory, NPL was skeptical that it could work and quite simply didn’t have the resources to build the machine even if it did. Because of the secrecy of Bletchley Park, Turing couldn’t explain that he knew the machine would work — so the machine would stay a theory until a pilot version was built by NPL well after he left in 1950.

Perhaps one of the most popular reasons why someone would recognize the name of Turing comes from something that happened in 1949 when Turing was the deputy director of the Computer Lab at Manchester University. He was working on artificial intelligence and proposed an experiment that would later become known as the Turing test.

Even now, the Turing test is given to determine whether or not an artificial intelligence is indistinguishable from a human.

As part of the test, Turing built a chess program for a computer that didn’t even exist yet. In 1952, and without a computer powerful enough to actually run the test, Turing played a game of chess with his colleague where Turing simulated the role of the computer, following the rules of the program.

His program ended up going 50/50 when he lost to his colleague, Alick Glennie but won the game against a former colleague’s wife.

A tragic end to a hero’s life

Throughout the entire movie The Imitation Game is a plot threaded in where someone breaks into Turing’s house and steals nothing — and the detective, played by Rory Kinnear in the movie, is trying to get to the bottom of it. Although the detective Kinnear plays purely fictional, the basis for these events happened when Turing met Arnold Murray.

Murray was a 19-year-old unemployed man at the time and met Turing outside the cinema just before Christmas at the end of 1951. The two saw each other periodically until, on January 23rd, 1952, Turing’s house was broken into.

Murray admitted the thief was an accomplice of his, and Turing reported the break-in to the police. During the ensuing investigation, Turing admitted a sexual relationship with Murray — something that was illegal at the time.

Both Murray and Turing were charged with gross indecency. At the initial proceedings, held about a month later, Turing took the advice of his brother and legal counsel and pleaded guilty.

On March 31st, 1952, Turing went to trial and was convicted. He was given a choice between one of two: Either he could go to prison, or he could go on probation — on the condition that he undergo a treatment intended to cure him of his homosexuality.

He accepted probation and treatment saying, “No doubt I shall emerge from it all a different man, but quite who I’ve not found out.”

For the next year, he was injected with DES, a treatment that not only caused Turing to be impotent but also caused gynaecomastia. As a result of the trial and conviction, Turing was stripped of his security clearance and barred from any cryptographic consulting. He was allowed to keep his academic job, but the US denied him an entry in 1952 when he tried to go there.

On June 8th, 1954, Turing’s housekeeper arrived early in the morning to find his body.

Turing had committed suicide the previous day, killing himself with cyanide. A half-eaten apple was found by his bed, and many assume this was the method used to kill himself.

Four days later, on June 12th, Turing followed in his father’s footsteps when his body was cremated, and his ashes were scattered at the Woking Crematorium.

Four years after Turing’s death, building on the pilot ACE they had constructed from Turing’s designs in 1950, the full-scale Automatic Computing Engine that Turing had drawn up at the National Physical Laboratory was built in 1958 — ushering in a new age of digital computing.

Following Turing’s sad ending, a lot of theories popped up surrounding his death. Some guess that because of Turing’s involvement with cryptography and because of growing tensions around the world following World War II that he was assassinated. There’s never been anything to prove this, though.

Some think his death was accidental. The most compelling of these being a theory that Turing accidentally inhaled cyanide from a gold electroplating apparatus, which uses potassium cyanide to dissolve the gold, that was in his room. But again, this has never been proven.

The apple wasn’t really anything unique, as Turing would often eat an apple before bed — sometimes not making it through the whole apple before dozing off.

For a while, some even speculated that Apple’s logo with the bite was in honor of Turing. This was repeatedly denied by Steve Jobs. Another theory, posed by some of Turing’s biographers, is that Turing was re-enacting a scene from his favorite Disney movie — Snow White and the Seven Dwarfs. Turing, in particular, enjoyed the scene where the Wicked Queen used an apple laced with poison — so it’s interesting that he was to die in a similar fashion.

No matter the actual cause, no one can deny that a grave atrocity led to the downfall of the man who Winston Churchill credited as having made the single biggest contribution to Allied victory in the war against Nazi Germany.

Alan Turing was literally tried and convicted for his homosexuality, something that almost undoubtedly had a significant effect on — if not being the sole cause for — his death.

It wasn’t until an internet petition started to put pressure on the British Government when it received more than 30,000 signatures in August of 2009 that Prime Minister Gordon Brown finally released a statement.

A portion of the official statement is as follows:

“Thousands of people have come together to demand justice for Alan Turing and recognition of the appalling way he was treated. While Turing was dealt with under the law of the time and we can’t put the clock back, his treatment was of course utterly unfair, and I am pleased to have the chance to say how deeply sorry I and we all are for what happened to him … So on behalf of the British government, and all those who live freely thanks to Alan’s work I am very proud to say: we’re sorry, you deserved so much better.”

On December 24th, 2013, Queen Elizabeth II officially signed a pardon for Turing’s conviction for gross indecency — effective immediately. It was only the fourth royal pardon since the conclusion of World War II.