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August 1843Reputable source · 2 sourcesDebated

Ada Lovelace publishes the first algorithm

A translator's footnotes turn into the first published computer program, for a machine that never ran

On the timeline · around August 1843 · Mechanical and Theoretical FoundationsMechanical and Theoretical FoundationsAda Lovelace publishes the first algorithm1830184018501860187018801890190019101920

Quick facts

Author
Ada Lovelace (Augusta Ada King, Countess of Lovelace)
Published
August 1843, in Taylor's Scientific Memoirs
Key contribution
Note G: an algorithm to compute Bernoulli numbers
Debated claim
Whether the algorithm was originally hers or developed jointly with Babbage

What happened

Ada Lovelace translated an Italian engineer's French-language memoir on Babbage's Analytical Engine and, at Babbage's suggestion, added her own notes. Her notes ran three times longer than the original memoir and were published in 1843. The last of them, known as Note G, laid out a step-by-step sequence of operations for the Analytical Engine to compute Bernoulli numbers, a set of numbers used in mathematical series. It is the first published description of a stepwise procedure written for a machine to execute. Lovelace also went beyond the arithmetic Babbage had in mind, writing that the Engine 'might act upon other things besides number' and could, in principle, compose music.

Why it matters

Note G is why Lovelace is often called the first programmer, a claim historians still debate given how closely she worked with Babbage on the ideas. What is not disputed is that she was the first to publish a concrete algorithm for a general-purpose machine and the first to describe computation as something that could go beyond arithmetic into symbols of any kind, an idea that would not become mainstream again for over a century.

How we know

The Computer History Museum's Babbage Engine project describes the Notes and Note G from its own historical record, and notes explicitly that 'biographers debate the extent and originality of Ada's contribution,' a genuine scholarly dispute rather than a settled fact.

Sources

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