It’s Ada Lovelace Day—a day to celebrate the accomplishments of women in science, technology, engineering and math. But aside from remembering her fabulous headdress and association with computers, how much do you know about the groundbreaking woman? Here are five things worth understanding as you celebrate:

She had some infamous relatives

Augusta Ada Byron was the only legitimate daughter of George Gordon, Lord Byron, the hedonistic poet who was famously called “mad, bad, and dangerous to know” by one of his many mistresses. Byron's other daughter, Allegra, was born from an affair with Claire Clairmont, who is the stepsister of Mary Shelley. The child was shunted off to a convent in Italy and died at age five after Byron refused to recognize her.

Ada was only slightly luckier: Though Byron married her mother, Annabella, in 1815, he did so only to escape public condemnation for his ongoing obsession with his half-sister, Augusta Leigh. Ada’s mother was well-educated and such an accomplished philosopher and mathematician that Byron fondly called her his “Princess of Parallelograms.”

She was one of her era’s most educated women—for a weird reason

The happy relationship between Byron and Ada’s mother was short-lived. Fearing that Byron had fathered a daughter through his ongoing affair with his half-sister, Annabella began to suspect that he was insane and separated from him. This led to something unexpected: an unparalleled education for Ada. Fearing that Byron’s insanity would rub off on her daughter, Annabella recruited the best tutors for Ada, enrolling her in what was effectively an intensive homeschooling program that covered everything from languages to science.

Ada proved to be a brilliant mathematician, and when she was 17 years old, she met Charles Babbage, an inventor who would change the course of her life—and computing history.

She was the first programmer. Or was she?

Babbage became Ada’s lifelong friend. They began to correspond about science, math and just about everything else. In 1834, a year before Ada married, Babbage had begun to plan what he called an Analytical Engine—a proposed computing system that used punched cards to multiply and divide numbers and perform a variety of data tasks.

When an Italian engineer wrote an article in French on the machine, Ada translated it into English. She added extensive notes of her own, which described a sequence of steps that could be used to solve mathematical problems. It was essentially the first computer program.

Since then, it’s been argued that Ada was not a programmer at all—that Babbage created the first operating instructions instead or that she did not have the knowledge to do so. But she demonstrated her intellectual prowess with a vision of using the machine to do things other than basic math. As the Ada Lovelace Project notes, the arguments made against her work are those commonly used to downplay women’s contributions to science and mathematics. Whether you believe that her notes constitute the first computer program or not, it’s undeniable that Ada Lovelace foresaw and contributed to the modern tech revolution.

Would her program have worked? Probably, but Babbage’s Analytical Engine was never built.

She inspired a language that makes modern defense and air systems work

Ada, who eventually married William King-Noel, the first Earl of Lovelace, is known as the “Countess of Computing.” That reputation earned her an astonishing namesake: Ada, a language that changed modern computing.

By the 1970s, the U.S Department of Defense was spending billions on embedded computing systems—code that was part of machines instead of a common language used by all. In an attempt to consolidate military computing and save money, the D.O.D. embarked on the most expensive coding project ever. The result was Ada, named after the computing pioneer.

Ada is still used worldwide today. Not only does it power the United States’ military weapons systems, but it is used in air traffic control, railroad transportation and even rockets and satellites. The language is decades old and has fallen out of favor in some circles, but others prefer to use it for its security and longevity—a move that speaks not just to the quality of the program, but of Ada’s lasting influence in computing.

Lovelace’s legacy lingers

After her death at age 36, Lovelace became a footnote to Byron’s biography. But as Annalee Newitz writes for io9, she was never completely forgotten. These days, her reputation is stronger than ever as the world sets out to reconstruct the long-ignored history of women in computing.

In 2009, a British social media technologist named Suw Charman-Anderson encouraged people to talk about women in science, technology, engineering and math whom they admire. That call evolved into Ada Lovelace Day, an international celebration of women in STEM that features tributes and events all around the world.

So is October 11 Ada Lovelace’s birthday? Nope, and it’s not her death date, either. As its founders explain, the second Tuesday in October was chosen for its convenience. But it’s never the wrong time to celebrate women’s often downplayed accomplishments in the sciences—or the woman who made so much of modern computing possible.