Eratosthenes Biography

(First Person to Calculate the Circumference of the Earth and Earth's Axial Tilt)

Born: 276 BC

Born In: Cyrene, Libya, Shahat, Libya

The Greeks were the earliest discoverers of much of the knowledge that went on to lay the foundations of scientific studies for thousands of years and one of the most important figures from that period is undoubtedly Eratosthenes, who was a mathematician, geographer as well as an astronomer of rare quality. Additionally he was also a music theorist which well and truly shows the sort of versatile knowledge and gifts that he possessed. Eratosthenes was responsible for bring to notice some of the most important discoveries in geography, astronomy and mathematics. Born in the Cyrene, the young lad was remarkably curious from an early age. He pursued higher education from Athens where he was taught by the best teachers of the day. Aristo of Chios and Arcesilaus in particular left a lasting impression on the budding philosopher. His reputation as a mathematician was affirmed when he measured the circumference of the earth using the shadows cast by the sun. He also made immense contribution to the field of geography by demarcating the five different climate zones existing in the earth. In fact the term geography was also coined by this eminent scientist. It can be unarguably said that this erudite scientist made discoveries that were way ahead of his time. Read on to know more about his life and works.

Quick Facts

Also Known As: Eratosthenes of Cyrene

Died At Age: 82


father: Aglaus

Born Country: Libya

Geographers Astronomers

Died on: 194 BC

place of death: Alexandria, Egypt

Cause of Death: Starvation

Childhood & Early Life
Eratosthenes was born in the year 276 BC to Aglaos and his wife; but the exact date of his birth is unknown. He was born in the city of Cyrene; which is located in present day Libya but used to be a part of the Greek empire.
Eratosthenes went to the then seat of learning in Athens for his education and was taught by the best teachers of the day. His teachers included the famous philosophers Ariston of Chios and Arcesilaus of Pitane who was also the principal at the celebrated ‘Platonic Academy’.
During his years as a student at the ‘Platonic Academy’, he became deeply interested in Plato’s philosophical writings and also showed a genuine flair for writing poems; which earned him plenty of accolades among his peers.
It was during his time at the academy that he produced his first well known work named ‘Platonikos’. The book looked at Plato’s philosophies from a mathematical standpoint.
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The ruling pharaoh Ptolemy III Euregetes recognised his talent as a scholar of rare quality and swiftly appointed him as the librarian of the ‘Library of Alexandria’ in 245 BC; which at the time was regarded as one of the greatest libraries of the world.
Eratosthenes was the first person to have measured the circumference of the earth, fairly accurately, in his time. He adopted an extremely simple method in which he used the shadows cast by the setting sun as the basis of his findings.
His next big project was in the field of Geography, a subject to which he contributed immensely. He was the one who is regarded as the ‘Father of Geography’.
He wrote the book ‘Geographika’ or Geography that was divided into three volumes and formed the basis of geographical studies. In the book this knowledgeable scholar had presented a fairly accurate map of the earth as well as the concept of climatic zones.
He was someone who had achieved things that were unthinkable in his time and one of his most remarkable findings was that a year had 365 days. He also explained the concept of a leap year and also calculated the earth’s diameter, during his illustrious career.
Eratosthenes worked on a number of theories in mathematics and his most significant achievement was in creating an algorithm that could determine prime numbers. At the time the algorithm could figure out prime number up to 127.
The great mathematician worked as the librarian at the ‘Library of Alexandria’ throughout his professional life and during that time he had made the library into the one of the biggest storehouse of knowledge in the world till it was destroyed by fire.
Major Works
His book titled ‘On the Measurement of the Earth’ is supposed to be one of the oldest books on Geography and the elements of the solar system. Ranking among his most important works, the book presented his findings related to circumference of the earth.
Considered a pioneering chronologist, he also wrote a book titled ‘Olympic Victors’ which chronicled the winners at the sports and athletic event that takes place to this day.
Personal Life & Legacy
There is no reliable information about his personal life. Eratosthenes lost his eyesight later on in life and committed suicide by starving himself in 194 BC.
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