longer existed during Hypatia's lifetime. Life Upbringing Hypatia was the daughter of the mathematician Theon of Alexandria (c. 335 – c. 405 AD). According to classical historian Edward J. Watts, Theon was the head of a school called the "Mouseion", which was named in emulation of the Hellenistic Mouseion, whose membership had ceased in the 260s AD. Theon's school was exclusive, highly prestigious, and doctrinally conservative. Theon rejected the teachings of Iamblichus and may have taken pride in teaching a pure, Plotinian Neoplatonism. Although he was widely seen as a great mathematician at the time, Theon's mathematical work has been deemed by modern standards as essentially "minor", "trivial", and "completely unoriginal". His primary achievement was the production of a new edition of Euclid's Elements, in which he corrected scribal errors that had been made over the course of nearly 700 years of copying. Theon's edition of Euclid's Elements became the most widely used edition of the textbook for centuries and almost totally supplanted all other editions. Nothing is known about Hypatia's mother, who is never mentioned in any of the extant sources. Theon dedicates his commentary on Book IV of Ptolemy's Almagest to an individual named Epiphanius, addressing him as "my dear son", indicating that he may have been Hypatia's brother, but the Greek word Theon uses (teknon) does not always mean "son" in the biological sense and was often used merely to signal strong feelings of paternal connection. Hypatia's exact year of birth is still under debate, with suggested dates ranging from 350 to 370 AD. Many scholars have followed Richard Hoche in inferring that Hypatia was born around 370. According to a description of Hypatia from the lost work Life of Isidore by the Neoplatonist historian Damascius (c. 458 – c. 538), preserved in the entry for her in the Suda, a tenth-century Byzantine encyclopedia, Hypatia flourished during the reign of Arcadius. Hoche reasoned that Damascius's description of her physical beauty would imply that she was at most 30 at that time, and the year 370 was 30 years prior to the midpoint of Arcadius's reign. In contrast, theories that she was born as early as 350 are based on the wording of the chronicler John Malalas (c. 491 – 578), who calls her old at the time of her death in 415. Robert Penella argues that both theories are weakly based, and that her birth date should