1939: World War II begins and electronic computing is forged

On 1 September 1939 German troops crossed the Polish border. Two days later Britain and France declared war. The Second World War had begun. Almost no one that day imagined that the coming conflict would also force into existence a radically new species of machine—the electronic digital computer—and thereby lay essential foundations for artificial intelligence.

The military suddenly needed calculations on a scale and at a speed no human team could match. Ballistic trajectories, cryptographic keys, logistical plans and, later, nuclear simulations all demanded relentless arithmetic. In Britain the secret Government Code and Cypher School at Bletchley Park assembled an extraordinary group of mathematicians and engineers. Among them was Alan Turing. The electromechanical Bombe devices they built, and above all the fully electronic Colossus machines that came online in 1943–44, were the first large-scale programmable electronic computers. Colossus helped break the Lorenz cipher used by the German High Command and shortened the war.

In the United States parallel efforts produced the Harvard Mark I and then ENIAC, unveiled in 1945 to calculate artillery firing tables. The mathematician John von Neumann, who worked on both the American projects and the theoretical design of EDVAC, crystallised the stored-program concept that remains the blueprint for virtually every computer in use today.

None of these machines was “intelligent.” Yet they proved that formal symbol manipulation could be performed automatically, reliably and at electronic speed. Turing’s wartime immersion in machine-assisted reasoning fed directly into his 1950 paper “Computing Machinery and Intelligence,” which posed the question that still defines the field: can machines think? The hardware lineage that began under the pressure of total war continued through transistors, integrated circuits, GPUs and the vast data-centre clusters that now train large language models.

Thus an invasion launched on a late-summer morning in 1939 became, through a chain of urgent engineering necessities, one of the indispensable preconditions for the artificial intelligence we live with today. The same silicon that once aimed guns and cracked codes now writes poetry, diagnoses disease and steers autonomous vehicles—an unforeseen legacy of that fateful 1 September.