Ada Lovelace wrote the 1843 notes describing an algorithm for Charles Babbage’s Analytical Engine.
Her notes accompanied her translation of an article by Luigi Menabrea about Babbage’s proposed mechanical computer. Lovelace added extensive explanations, including a method for calculating Bernoulli numbers. This is widely described as the first published computer program.
Lovelace also recognized that a programmable machine could manipulate symbols beyond numbers, including music or language. That insight was unusually broad because Babbage’s machine was never completed. People sometimes call her the first computer programmer without noting that the machine she programmed existed only as a design.
Her notes were published in 1843 under her initials, A.A.L. She was the daughter of poet Lord Byron and mathematician Anne Isabella Milbanke.