The first known female mathematician was Hypatia of Alexandria (370–415), who was probably tutored by her mathematician and philosopher father, Theon of Alexandria, who taught at the Museum of Alexandria in Egypt. Around 400, she became the head of the Platonist school at Alexandria, lecturing on mathematics and philosophy. It is thought that she also invented the plane astrolabe, the graduated brass hydrometer, and the hydroscope (possibly with Synesius of Greece, once her student and later her colleague at the school). Little is known of her writings—thought to be works on mathematics, astronomy, and philosophy—and more legend is known of her than any true facts. It is thought that she was eventually killed by a mob egged on by a Christian bishop, Cyril, who felt the contrary-to-the-norm (and pagan) Hypatia did not know her place.