Theon lived in the turbulent closing period of the fourth century A.D. and was the author of a commentary, in eleven books, on Ptolemy's Almagest.
Theon's daughter, Hypatia, was distinguished in mathematics, medicine,
and philosophy, and wrote commentaries on Diophantus Arithmeticaand
Apollonius conic Sections. she is the first woman mathematician to be mentioned
in the history of mathematics. Her life and barbarous murder by a mob
of fanatical Christians in March, 415, are reconstructed in Charles Kingsley's