Claudius Ptolemy was born in Alexandria, Egypt in 100 A.D. and died in the same city in 170 A.D.. He was a Greco-Roman mathematician and astronomer, and his teacher was Theon of Smyrna. There is not much known information about his personal life.

Ptolemy created the geocentric theory, which was where the Earth is at the center of the universe, and he used geometric models to calculate the positions of the sun, the moon, and the rest of the planets in our solar system. He also wrote a series of 13 books called "The Almagest" which explained his mathematical theory of how the sun, the moon, and the planets move throughout our solar system. This is said to be his most important work he ever created. Another series of books he wrote was called