My father Theon headed the Mouseion, an exclusive school in Alexandria, and his great achievement was a corrected edition of Euclid's Elements. I took up his Plotinian Neoplatonism and his editor's craft, and in mathematics I came to surpass him.
Synesius wrote asking me to construct a hydroscope, a hydrometer for measuring the density of liquids, and described it in detail, trusting that I could make it from his words alone.
For the long division that Ptolemy's astronomy needs, I set out a tabular method in my edition of the Almagest. It lays the computation out step by step so a student can work through it.
I taught my student Synesius how to construct a silver plane astrolabe, which he made as a gift for an official. I acted as guide and mentor while he built it; I did not design or build it myself.
My generation of scholars did not publish original treatises. We kept the classical mathematical works alive by commenting on them. After the Mouseion closed and the Serapeum fell, I put my effort into preserving those books and making them usable for students.
Like my father, I set aside Iamblichus's teaching and taught the original Neoplatonism of Plotinus. It was a moderate, less polemical philosophy, open to Christian students, and I hoped it could show that philosophy and Christianity can coexist.
I taught my students that a Neoplatonic philosopher must bring the highest moral standards into political life and act for the good of fellow citizens. In 413 my former student Synesius held me to that same teaching.
When Alexandria split between Bishop Cyril and the Roman prefect Orestes, Orestes kept coming to me for advice: pagans and Christians alike respected me, I had no part in the earlier conflict, and my reputation as a wise counselor was impeccable.
I taught philosophy in Alexandria's school, which was second only to Athens, to students who came from all over the Mediterranean. I lectured on Plato and Aristotle, and I also lectured in public, in the streets of the city.
Besides my Diophantus edition, I wrote a commentary on Apollonius of Perga's treatise on conic sections. It is advanced mathematics, and commenting on it is why most scholars count me among the leading mathematicians of my day.
