History of mathematics: Eratosthenes and Euclid

Eratosthenes
Born in 286 BC Cyrene he was a versatile researcher who also wrote plays. It says he was left to starve; wrote several works including "chronograph" that dated events by the Olympics. Explain the motion of celestial bodies through the armillary sphere, also deals with the tide, his geography is mathematical.
He also measured the circumference of the earth: consider Alexandria and Syene on the same longitude and Syene on the tropic. Through the zenith angle of the shadow in Syene and Alexandria with the proportions calculated the circumference of the earth (between Syene and Alexandria there are 5000 stadia, Egyptian unit of measurement).
Mesolabio: tool for finding cube roots. Sieve: you write all the numbers, you delete all the multiples to the root of the penultimate number, one is not a prime number.

Euclid
He was born circa 300 BC Alexandria, is sometimes confused with Euclid of Megara, however, was that before.
Elements: speaking of arithmetic, geometry, algebra (including geometric), Euclid's postulates, including about 650 theorems.
Demonstration of infinitude of prime numbers: it is assumed a maximum number larger, multiply all prime numbers and add a unit resulting in a prime number greater than he had set as a maximum. Among the theorems can remember the famous theorems of triangles and parallel lines.

History of mathematics: John Napier

Napier

John Napier also known as Nepair (or Neper) born in 1550 and from an early age is recognized as a genius. At 13 he attended the faculty of theology; He tooks the side of the Anglicans. Fails in the theological he retreats on mathematics.

It's thought that he wasn't the first in the invention of logarithms (maybe first came Jacob Buergi) but Napier used them as a means of calculation and was the true inventor of logarithms as we know them today. The basic "e" most likely was used in the construction of the Parthenon and the pyramids in Egypt. He is remembered also for the design of weapons such as tanks and burning mirrors. At Napier is also called a unit, the "Napier" that is a unit of telecommunications.