Ada Lovelace's notes on the Analytical Engine published (1843)

In 1843, Ada Lovelace published her translation and extensive annotations of Luigi Menabrea's sketch of Charles Babbage's Analytical Engine in Taylor's Scientific Memoirs. The work included Note G, an algorithm often cited as the first published computer program, though Babbage's earlier private notes predate it. The publication resulted from Babbage's 1840 lectures in Turin, transcribed by Menabrea and subsequently translated by Lovelace.

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Background and detail

Background. The Analytical Engine was first described in 1837 as a successor to Babbage's simpler difference engine. Babbage developed numerous programs for the engine between 1837 and 1840. In 1840, Babbage visited Turin at the invitation of Giovanni Plana, giving the only public lectures on the Analytical Engine. Luigi Menabrea transcribed these lectures into French, publishing them in 1842.

Translation and Annotation. In 1842, Charles Wheatstone approached Lovelace to translate Menabrea's paper, and Babbage asked her to add her own notes. Lovelace had become interested in the engine eight years earlier, having met Babbage in 1833 through Mary Somerville. Her translation and notes were published in the September 1843 edition of Taylor's Scientific Memoirs under her initials AAL.

Note G and Controversy. The algorithm in Note G is often called the first published computer program. However, Babbage's personal notes from 1837 to 1840 contain earlier programs. Bromley notes several dozen sample programs prepared by Babbage between 1837 and 1840, all substantially predating Lovelace's notes. The claim that Lovelace's work is unambiguously the world's first computer program is contested.

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