Proclus was a teacher of the Neoplatonic school and was a supporter of paganism. He was born at Constantinople on February 8, 412. He studied in Alexandria and in the year 431 he went to Athens to study at the Academy that had been founded by Plato some 800 years earlier. He would eventually become the head of the Academy. He died on April 17, 485.

Although Proclus was more of a philosopher than a mathematician, his mathematical work is not without significance. As is the case with most mathematicians of his time, Proclus is not primarily known for his original mathematical contributions. However, the theorem that if a line segment of fixed length moves with its endpoints on two intersecting lines, a point on that line segment describes a portion of an ellipse is attributed to him.

Perhaps Proclus' most significant contribution of a mathematical nature was his Commentary on Book I of the Elements. When writing this book, he had a summary of Eudemus' History of Geometry; both Eudemus' work and the summary that Proclus used are now lost, making Proclus' work the main extant source of the history of geometry before Euclid.

Sources used (see bibliography page for titles corresponding to numbers): 38.