Hypatia of Alexandria
“There was a woman at Alexandria named Hypatia, daughter of the philosopher Theon, who made such attainments in literature and science as to far surpass all the philosophers of her own time. Having succeeded to the school of Plato and Plotinus, she explained the principles of philosophy to her auditors, many of whom came from a distance to receive her instructions.” -Socrates of Constantinople
"The first historically noted woman in mathematics. As head of the Platonist school at Alexandria, she also taught philosophy and astronomy.
As a Neoplatonist philosopher, she belonged to the mathematic tradition of the Academy of Athens, as represented by Eudoxus of Cnidus; she was of the intellectual school of the 3rd century thinker Plotinus, which encouraged logic and mathematical study in place of empirical enquiry and strongly encouraged law in place of nature." - Wikipedia
It is often said that the ultimate goal of science is to describe every detail of the universe with pure math alone. In this sense I consider Hypatia to be the mother of all science.
She was killed by a mob of zealots who believed she was influencing the local Governor. This event shocked the pagan and moderate populations of Alexandria but only further emboldened the radical elements. It is sometimes considered the first historically notable witch-hunt. The tragedy of Hypatia's death highlights the dangers of superstition, misogyny and anti-intellectualism.
Most of all, I believe Hypatia has a place in this thread because she was known and admired for (among other things) her intelligence, wit and confidence. She thrived as a single woman and stood as an equal with the most powerful men of Alexandria, all in a culture that was becoming increasingly barbaric and would barely even consider the concept of women's equality till well over a thousand years in the future.