Euclid, a Greek mathematician, lived in Alexandria at the time of Ptolemy I and did his most significant work in approximately 300 BCE. The biographical tradition concerning Euclid is scant, and on the main, unreliable. His major surviving work is his Elements of Geometry; other less important treatises on mathematics and optics are also extant, although several of works of his that are mentioned in ancient sources have not survived to the present. A long commentary on the Elements by Proclus, a Platonic philosopher, confirms a probable association of Euclid in his early career (possibly as a student) with the Platonic academy in Athens.
Euclid`s Elements has set down the basic principles of plane geometry as it has been studied from the Greeks through the present and he is often referred to as the `Father of Geometry.`