Euclid of Alexandria, a Brief Bio

Euclid of Alexandria is one of the most important and influential mathematicians in history. Living in ancient Alexandria, he wrote The Elements, a geometry textbook used in some places until the twentieth century. His work in geometry provided the foundation on which all future mathematicians were educated.

For a man of such great significance to the world of mathematics, little is known about his actual life. Euclid is thought to have lived from 325–265 BC, mostly in Alexandria. He was taught at The Academy in Athens, founded by Plato, and probably tutored another great mathematician, Archimedes. Euclid also founded a great mathematics school in Alexandria. Little was ever written about Euclid, and the available information is scarce and of questionable accuracy. Much of what we do know comes from authors like Proclus who lived centuries later, writing about his books rather than his life.

If little has been made of Euclid's life, the opposite is true of his book. The Elements was used as the primary geometry resource for over 2000 years, and his lessons could still be used today. Although it contains 13 volumes, much of the work may not be entirely Euclid's own — some chapters appear to be written in different styles and geared to different audiences, suggesting he incorporated other mathematicians' work into his own.

Each volume begins with definitions and postulates, followed by theorems. Euclid then proves each theorem using those foundations, mathematically proving even the most obvious-seeming results. His work was translated into Latin and Arabic, and was first printed in mass quantity in 1482 — ten years before Columbus, but 1800 years after it was written. From that point until the early 1900s, The Elements was considered by far the best geometry textbook in the world.

Although he may not have written The Elements entirely on his own, his other works are certainly his alone: Data, Optics, Phaenomena, and On Divisions of Figures. Data focuses on finding unknown measurements when others are given. Phaenomena covers planetary motions. Optics attempts to prove the then-common belief that sight was created by rays coming from the eye, rather than light entering it.

Euclid was apparently a patient man with a dry sense of humor. King Ptolemy once asked whether there was an easier way to study geometry than working through all the theorems. Euclid replied, "There is no royal road to geometry," and sent one of the most powerful rulers of his time back to his studies. On another occasion, a student questioned the value of learning geometry. Euclid responded by giving the student a coin, saying he "must make gain out of what he learns."

His primary legacy is The Elements — 2000 years of mathematical education built on his proofs and theorems. While students no longer read directly from his writing, today's geometry textbooks are still rooted in Euclidean methods. It's fitting that he is called "The Father of Geometry."