Ada Lovelace

Ada Byron, later the Countess of Lovelace, was the only legitimate child of the poet Lord Byron, and her mother made sure she never met him. She also made sure Ada met mathematics, on the theory that numbers would keep her daughter from inheriting her father’s wildness.

At seventeen she met Charles Babbage, who had designed a machine that could calculate tables by itself: the Analytical Engine. It was never built, made of brass and steam and good intentions. Ada studied it harder than anyone else alive.

In 1843 she translated an Italian paper about the engine and appended her own notes, longer than the original. In those notes she wrote out a set of steps the machine could follow to compute Bernoulli numbers, and explained that such a machine could go beyond arithmetic to compose music or graphics, if only it were fed the right rules.

That is the shape of a computer program, written a hundred years before any computer ran one. She also saw something Babbage did not: the machine was a symbol manipulator, not a calculator. That leap is what her name now stands for.

She died of cancer at thirty-six, the same age her father had died. The language Ada is named for her, and every October people meet to remember her work.