Euclid
By Michael Thomsen

Euclid was born in approximately 365 BC and died in approximately 300 BC He lived in Alexandria, Egypt where he was a prominent and famous teacher. Very little reliable information is known about his life. Ironically, he is, perhaps, the most famous mathematician from this period. Euclid gained much of his fame from his treatise on geometry, The Elements. This treatise served as a basis for most of the teachings and study in mathematics for nearly two thousand years. One of the notable ideas in The Elements was the famous fifth, or parallel, postulate. This idea states that only one line can be drawn from a line to a parallel point. This idea became the cornerstone of "Euclidean" geometry which survived into the nineteenth century. The Elements was divided into thirteen books on a variety of subjects: books 1-6 dealt with plane geometry, books 7-9 dealt with number theory, book 10 concerned Exodus's theory of irrational numbers, and books 11-13 spoke about solid geometry. Another famous aspect of The Elements was a discussion and a thorough mathematical proof of regular polyhedra. In fact, the rigor of that proof served as a model for the people who later pioneered calculus. As remarkable as Euclid's works was, it was not infallible. Approximately two hundred and fifty years after the publication of The Elements, a book entitled Zeno of Sidon was published, in which a great number of subtle assumptions were exposed in Euclid's work. Even still, the presence of Euclid's ideas dominated mathematics and geometry for nearly two thousand years, and even today appear in various forms.