Ada Lovelace (1815–1852) was an English mathematician, the daughter of the wild poet Lord Byron, and — a century before any computer existed — the person who first grasped what a computer could really be. Her mother steered her hard toward maths, hoping to keep the "dangerous" poetry out of her. It didn't quite work: Ada called her own style "poetical science."
Ada worked with Charles Babbage on his never-built Analytical Engine. Translating a paper
about it, she added notes three times longer than the original — and in them wrote what is
often called the first computer program: a step-by-step recipe of
Ada thought not — the machine, she insisted, "has no pretensions to originate anything." It only does what we order it to do. This became known as "Lovelace's objection," and Alan Turing took it seriously enough to argue against it a hundred years later. Not bad for a debate she started in a footnote.