**Euclid of Alexandria**

Euclid of Alexandria was born about 325 BC and he died about 265 BC He is
called the Father of Geometry, and is best known for his treatise on
mathematics, *The Elements*. It is said that this treatise may make Euclid
the leading mathematics teacher of all time.

Euclid most likely came from a rich family, because as a young child, he went to Plato’s school in ancient Greece, where only the rich were educated. After he finished school he went to Alexandria, where he discovered and wrote his theories on geometry.

Euclid of Alexandria is often confused with Euclid of Meguro, who was also a
leading mathematician. Euclid was a popular name at that time, but *The
Elements* set Euclid of Alexandria apart from all the others.

*The Elements* consists of 13 Volumes that summarize, describe, and
explain all of the rules of geometry that we use today: Volumes 1-6: Plane
Geometry; Volumes 7-9: Number Theory; Volume 10: Exodus’ Theory of Irrational
Numbers; Volumes 11-13: Solid Geometry.

The first edition of The Elements was printed in 1492, and millions of copies have been sold since then. It was pulled out of schools in 1901, but the theories and principles remained the same, simply rewritten in a modern form.

*The Elements* begins with definitions and five postulates. The first
three postulates are postulates of construction; foe example, the first
postulate states that it is possible to draw a straight line between any two
points. The postulates assume that the existence of points, lines, circles, and
other geometric objects are deduced from the fact that points, lines, etc.
actually exist. Euclid’s postulates led to Euclidean Geometry, and it wasn’t
until the 19th century that they were dropped, and non-Euclidean geometry was
studied.

In his treatise, Euclid also wrote axioms, which he called "common notions". They aren’t specific geometrical properties, but they are assumptions that allow mathematics to proceed as a deductive science.

Euclid’s Elements is remarkable for the clarity with which the theorems are stated and proved. The standard of rigor was to become a goal for the inventors of calculus centuries later.

Euclid wrote his treatise after such pupils of Plato as Eudoxus, and before Archimedes. He was the leader of a team of mathematicians working at Alexandria, and they all contributed to writing the "Complete Works of Euclid", even continuing to write under Euclid’s name after his death. He is described as being nice, but often sarcastic. Without his work, and his ability to compile all of his ideas into a massive format, Euclid of Alexandria would never have earned the title of the Father of Geometry.