In Alexandria, the second largest city in Egypt, one of the greatest mathematicians to ever exist on Earth was born in 325 BCE. This mathematician’s name was Euclid. He is said to be the son of Naucrates. Euclid was named after Euclid of Megara, a philosopher who lived one hundred years before him. Not only was Euclid a mathematician and a scientist, he was an author as well. Euclid’s most well-known writing was a series of books called “The Elements”. The Elements were on subjects like circles, irrational numbers, 3D geometry, plane geometry and number theory. The Elements consist of five postulates and definitions. These books explained simple theories to detailed explanations of what a line is. Although he did not discover most of these he was the first to publish a series about them. Euclid also wrote “Data”, “which looked at what properties of figures can be deducted when other properties were given.” He wrote “On Divisions” “which looked at constructions to divide a figure into two parts with area of given ratio.” “Optics” “was the first Greek book on perspective”. “Phaenomena” was about mathematical astronomy. Euclid also wrote many other books that were lost in history such as Surface Loci, Porisms, Elements of Music, Conics, and Book of Fallacies. He is considered to be the father of geometry because of the theories he discussed in his books. Some of which still have not been proven to be true in this day and age. Although there is very little known about Euclid he is also considered to be the greatest math teacher in the world. In fact after he died in 265 BCE his fellow mathematicians continued to write books under his name.