Hypatia

Hypatia was a Neoplatonist philosopher, mathematician and astronomer who taught in Alexandria in the late fourth and early fifth centuries CE. The daughter of the mathematician Theon, she became the city's most respected teacher of philosophy and an adviser to its political leaders, before being murdered by a Christian mob in 415. She is the first woman mathematician whose life is reasonably well documented, and her death made her an enduring symbol, often in ways that go well beyond the evidence.

Hypatia was born in Alexandria, the great Greek city of Roman Egypt, at a date that cannot be fixed. Scholars have proposed years between about 350 and 370; the later date rests on a description of her youthful beauty around 400, the earlier on a chronicler's statement that she was old when she died. Her father, Theon, was a well-known mathematician and astronomer, and a member of the city's Museum, the old centre of learning. He produced editions and commentaries on standard works, including the Elements of Euclid and the astronomical writings of Ptolemy. Nothing is known of her mother. Hypatia was trained by her father in mathematics and astronomy and went on to surpass him, especially in philosophy.

By the 390s Hypatia was head of a school in Alexandria, teaching mathematics, astronomy and philosophy. Her philosophy belonged to the Neoplatonic tradition founded by Plotinus, which interpreted Plato and Aristotle as guides to the soul's ascent towards the divine. Ancient sources describe her lecturing in public in the philosopher's cloak, as well as teaching a smaller circle of devoted students privately.

Her students came from wealthy and influential families across the eastern Mediterranean, pagans and Christians alike. The best known is Synesius of Cyrene, who later became a Christian bishop in Libya and whose surviving letters address her with great reverence. They show that she taught her students how to build an astrolabe, an instrument for calculating the positions of the stars, and that she advised Synesius on making a hydrometer, a device for measuring the density of liquids. Neither instrument was her invention, but the letters show her practical skill. Hypatia never married and was famous for her self-control and modesty, and Christian as well as pagan writers praised her virtue.

None of Hypatia's writings survives under her own name, and their contents have to be reconstructed. The Byzantine encyclopedia known as the Suda credits her with a commentary on the Arithmetica of Diophantus, a work on algebraic problems; a commentary on the Conics of Apollonius of Perga, on curves such as the ellipse and parabola; and an astronomical work, the Astronomical Canon, probably connected with Ptolemy's tables. Some scholars believe parts of her Diophantus commentary survive in the text of the Arithmetica as it has come down to us. Theon's commentary on the third book of Ptolemy's Almagest states that the edition was revised by his daughter Hypatia, which suggests that she prepared or corrected the version of the Almagest that later readers used. Her work seems to have centred on teaching, editing and explaining existing texts rather than on new discoveries, the normal pattern for scholars of her time.

Hypatia lived through a period of religious and political change in the Roman Empire, as Christianity became the official religion and pagan worship was banned. In 391 a Christian crowd encouraged by the bishop Theophilus destroyed the Serapeum, Alexandria's great temple of Serapis. Hypatia does not seem to have been involved in the pagan resistance to this, and she continued to teach undisturbed for many years.

In 412 Theophilus was succeeded as bishop by his nephew Cyril, who soon came into conflict with Orestes, the imperial prefect of Egypt. Clashes between the Christian and Jewish communities led to the expulsion of many Jews from the city, and monks who came in from the desert attacked Orestes in the street; one of them hit him with a stone and was then tortured to death on his orders. Hypatia was close to Orestes and was regarded as one of his most important advisers. Rumours spread among Cyril's supporters that she was preventing a reconciliation between the prefect and the bishop.

In March 415, during Lent, a crowd of Christians led by a church reader named Peter seized Hypatia as she was returning home. They dragged her into the Caesareum, a former temple of the imperial cult that had become a church, stripped her and killed her with ostraka, a word that may mean roof tiles, potsherds or shells. They tore her body apart and burned the remains outside the city.

The main account comes from the church historian Socrates Scholasticus, writing a few decades later, who condemned the murder as a disgrace to the church of Alexandria. The pagan philosopher Damascius, writing in the next century, blamed the envy of Cyril. Whether Cyril ordered or encouraged the killing remains disputed; most historians see it as the outcome of the political feud he had stoked, rather than of an explicit order. The murder shocked the eastern empire, but no one is known to have been punished.

Hypatia's school did not end with her, and Neoplatonism continued in Alexandria and Athens for more than a century. Her later fame grew from the story of her death. Enlightenment writers such as Voltaire and Edward Gibbon used her as a symbol of reason destroyed by religious fanaticism, and Charles Kingsley's 1853 novel Hypatia made her a romantic heroine. In the twentieth century she became an icon of feminism and of science, and the 2009 film Agora dramatised her life. Many popular versions add claims that historians reject, such as linking her death to the destruction of the Library of Alexandria, or crediting her with inventing the astrolabe. Modern scholarship presents her as a gifted teacher and editor of mathematical texts, and a respected public figure, who belongs to the final chapter of Hellenistic and Roman philosophy.