Ada Lovelace is a celebrated role model for women in technology.
In an article published in 1843, she imagined a future in which programmable machines would be essential to the progress of science, and might even be used to create art and music.
We are now living that future.
So is Ada Lovelace our first tech visionary? Or, as some critics now claim, was her contribution to computer science vastly overrated?
Many of Ada Lovelace's letters are stored in Oxford's Bodleian Library and are about to be heard for the first time on BBC Radio 4, voiced by Oscar-nominated actress Sally Hawkins.
The picture of Ada that emerges from her correspondence is of a passionate, ambitious and flawed individual.
At times, Ada certainly had an exaggerated sense of her own destiny. Many of her letters are very long and self-obsessed and often a bit over the top. And it seems clear that she experienced many manic episodes.
But despite, or perhaps because of, constant battles with her mental and physical health, Ada pursued her interest first in mathematics and later in Babbage's engines with passion and zeal.
And, in many ways, Ada Lovelace anticipated our Digital Age, in Victorian times.
It was an extraordinary leap of imagination. No surprise perhaps for the abandoned daughter of the romantic poet, Lord Byron.
Ada's single mother, Lady Byron put her under a strict regime of moral and mathematical training from an early age, hoping it would counter any dangerous "poetical" tendencies she might have inherited from her notorious father. She also regularly prescribed "more maths" for her periods of mental instability.
Surprisingly perhaps, Ada's passion for mathematics persisted.
Aged 26, married with three small children, she embarked on a mathematics correspondence course. Letters to her distinguished tutor reveal that she was working at the level of a bright first year undergraduate.
So, Ada Lovelace was a good, but not a brilliant mathematician.
She first met Charles Babbage and one of his innovative calculating machines, the Difference Engine, at a party in his London drawing room, when she was 17.
He was to change her life but not in the way most 19th century debutantes like Ada would have imagined.
Years later, Ada made Babbage a bold proposal. She offered to work as his assistant. It was a remarkably pushy move, especially given the stifling social conventions that governed her world. And it worked.
Babbage was now working on a design for a new machine, which he called the Analytical Engine. Unlike the Difference Engine, which could only add, the Analytical Engine worked much more like a modern computer and could be programmed to carry out almost any sequence of logical steps.
The only published description of the Analytical Engine was a French-language article by an Italian engineer, Luigi Menabrea. Ada translated the article for publication in a British journal, and Babbage encouraged her to add a set of notes, describing more fully how the Engine worked.
Ada's worked furiously on the Notes which ended up twice as long as the original article. And Babbage, an eminent mathematician as well as an inventor, was impressed.
Ada's Notes on Babbage's engine include some visionary statements about its potential and limitations.
"The Analytical Engine has no pretensions whatever to originate anything. It can do whatever we know how to order it to perform…But it is likely to exert an indirect and reciprocal influence on science itself."
Ada's Notes on Babbage's engine also include tables setting out the sequence of operations the machine would have to go through to find the solution to an algebraical problem, such as a sequence known as Bernouilli's numbers. This is why some contemporary writers have called Ada the "world's first programmer" but, strictly speaking, these tables were not computer programmes.
She does, however, seem to have understood the significance of Babbage's engines better than he did.
Some critics claim that Ada's reputation is based on Babbage's brilliance not her own. Ada and Babbage certainly collaborated closely. A series of fraught letters flew between them in the rush to get the Notes published. At one point Ada accused Babbage of losing Note G at the printers.
But there's no reason to doubt that Ada wrote the Notes herself.
Perhaps Ada's greatest talent was the way she combined an understanding of mathematics with a vivid and "poetic" imagination.
She was the forerunner not of today's coders and hackers, but of the visionaries who imagine how the next generation of technology might change the world.
She was a Victorian tech visionary.
The letters of Ada Lovelace will be broadcast on Radio 4 on Monday 14th and 21st Sept at 11am. And are available to download here.
Calculating Ada: The Countess of Computing will be broadcast on BBC Four on Thursday 17th September at 9pm.