Theon of Smyrna (70–135)

Known as The Old Theon by Theon of Alexandria, Theon the Mathematician by Ptolemy and Theon the Platonist by Proclus, he was a Greek philosopher and mathematician, who was purported to have had, as a student, Ptolemy, the great Greek mathematician, astronomer, geographer and astrologer.

Theon of Smyrna was deeply influenced by the Pythagoreans and best remembered as the author of a handbook on Pythagorean harmony and for several widely cited observations of Mercury and Venus.

He wrote a textbook on arithmetic that he claimed was an introduction to Plato’s mathematics.

Instead, the book was more about the interrelation of arithmetic and prime numbers, geometry and squares, music and astronomy.

Theon’s most influential extant writing, Theonis Smyrnaei Platonici Eorum, quae in Mathematicis and Platonis lectionem utilia sunt, Exposition, was first translated, from Greek to Latin by Ismael Boulliau, the noted French astronomer.
Theon of Smyrna (70–135)