Euclid is a mathematician who lived in Greece. There are few things about his life precisely. It is just known that he was borned in approximately B.C. 325 and he wrote "Element" at the age of 40.
Euclid was a successful textbook writer. He wrote many books, and "Element" is the most famous one. It has been printed more than 1000 times since the invention of printer. It also has been the school textbook of geometry for more than 2000 years. Euclid integrated the mathematic knowledge and organized so well that he became one of the most respected mathematician.
"Element" consists of 13 books. It has 465 thesis in them. There are not only geometry but also algebra in these books.
One famous anecdote about Euclid and king Ptolemaeos has been told. It was the special party which celebrated the 1st birthday of the university. King Ptolemaeos drank a toast and said,
"Euclid, I started to read your geometry books. I praise your nice work."
Everyone nodded their head as the meaning of agreement. Euclid modestly lowered his head. As always, he was modest and quiet. King Ptolemaeos keeped saying,
"However, I am a pretty busy person as you know. I can hardly make time because I have to rule the country. Isn't there any easy way to learn math, Euclid?"
Euclid said in a polite attitude,
"Sorry, Your Majesty. As we know, there are two different ways in Egypt. One is for your majesty, and the other is for common people. However, in geometry, there is no way for only your majesty."