Eratosthenes was an illustrious ancient Greek polymath who had expertise in mathematics, astronomy and geography. He had inclination toward arts as well as music and poetry composition. At the Library of Alexandria, he was the chief librarian where he read books on a variety of disciplines that expanded his knowledge extensively. He is accredited for inventing the terminology geography including the formal establishment of the discipline. The circumference of the Earth and the tilt of the Earth’s axis was first calculated by him. Moreover, he founded the scientific chronology.
Eratosthenes of Cyrene was born in 276 BC to Aglaos. Cyrene became the center of knowledge at that time and young Eratosthenes received training in social discourse, physical skills, arithmetic, music and poetry. Subsequently, he went to Athens to further his horizons and expand his knowledge. Zeno of Citium taught him stoicism, a philosophy on personal ethics based on the system of logic and modesty. He was then mentored by Ariston of Chios who led a school of thought in cynicism. Arcesilaus of Pitane, the head of the Platonic Academy took him under his wing as his pupil. Platonikos was his first scholarly work which focused on the mathematical basis of Plato’s philosophical work.
Furthermore, Eratosthenes had a propensity for art and spent time with Callimachus researching the art of poetry. He was a gifted poet with astounding imagination and sensibility. One of his poems that he wrote, Hermes is an illustration of god’s life composed in hexameter. Besides religious and spiritual themes he also touched upon the plight of a mythical character in his account of suicide of an Athenian eponymous maiden, Erigone. Chronographies, is one of his compositions, a systematically arranged text, detailing all the significant events in chronological order. With its first chapter on Trojan War, it is still a critically appreciated and accurate historical data to present day.
The discipline of mathematics is not complete without Eratosthenes magnificent contribution to it. He was a close acquaintance of Archimedes and they often exchanged notes on several cross-disciplinary areas of math. He invented the armillary sphere, a model of objects in the sky, in 255 BC. Additionally, he calculated the circumference of the Earth by incorporating the data of angle of elevation of the Sun at noon. Inclusion of Egypt in calculation of the circumference of the Earth was also his preference. He was responsible for sketching the map of the Earth from its knowledge of size and shape.
While working as a librarian he came across abundance of knowledge on representation of world from multifarious travelogues that he came across. He pieced together all the information that he could gather from those books in his three volume work, Geographika. It maps out the entire world while also making precise division based on five climatically diverse regions. It presents two temperate zones, two freezing zones and the equator and tropics comprising one last zone.
‘Suda Lexicon’ is the term that was used to describe the jack of all trades that was Eratosthenes. He was a highly skilled polymath and proved his mettle at a variety of things yet he was still not recognized, thus he was called Beta. He tried calculating the diameter of the Sun by multiplying Earth’s diameter 27 times. He constructed a calendar using his predictions about the ecliptic of the Earth and came up with a solution for Doubling the Cube which was considerable achievement for him. In addition to that he composed an algorithm for finding prime numbers that is now called Sieve of Eratosthenes.