Hypatia
Hypatia (born 350–370; died 415 AD) was a Hellenistic Neoplatonist philosopher, astronomer, and mathematician, who lived in Alexandria, Egypt, then part of the Eastern Roman Empire. She was a prominent thinker of the Neoplatonic school in Alexandria, where she taught philosophy and astronomy. She is the first female mathematician whose life is reasonably well recorded. Hypatia was renowned in her own lifetime as a great teacher and a wise counselor. She is known to have written a commentary on Diophantus's thirteen-volume "Arithmetica", which may survive in part, having been interpolated into Diophantus's original text, and another commentary on Apollonius of Perga's treatise on conic sections, which has not survived. Many modern scholars also believe that Hypatia may have edited the surviving text of Ptolemy's "Almagest", based on the title of her father Theon's commentary on Book III of the "Almagest".
Charlotte Scott
Moving to the United States in 1885, she became one of eight founding faculty and Associate Professor of Mathematics at Bryn Mawr College, and Professor from 1888 to 1917. She was the first mathematician at Bryn Mawr College and the first department head. During this period she directed the PhD theses of many pioneering women mathematicians. Of the nine women to earn doctorates in mathematics in the nineteenth century, three studied with Scott.