Eratosthenes Birthday & Fun Facts

Height, Age, Net Worth, Biography & More

Akinwalere Olaleye
Feb 08, 2024 By Akinwalere Olaleye
Originally Published on Dec 01, 2023
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About Eratosthenes

Eratosthenes, born in 276 BCE in Cyrene (known today as Libya), was a renowned Greek scientist and polymath. His extensive knowledge of mathematics, geography, astronomy, poetry, music, and philosophy positioned him as a prominent figure in various disciplines. Acknowledged as the Father of Geography, Eratosthenes laid the groundwork for this academic field. He used the summer solstice to accurately calculate planetary distances and developed a technique to identify prime numbers. He also designed the leap-year calendar.

As a scholar, Eratosthenes was the chief librarian at the Library of Alexandria. He became the first person to measure the Earth's circumference accurately, leveraging comprehensive survey data available to him at the Library. Eratosthenes was the first to calculate the Earth's axial tilt and developed the first global projection of the world. Eratosthenes established scientific chronology using Egyptian and Persian records to date pivotal events, like the Sack of Troy in 1183 BCE. He died in Alexandria, Egypt, in 194 BCE.

Childhood And Education

Eratosthenes was born in 276 BCE, in Cyrene. His father's name was Aglaos, but not much details are available about his mother. As a young Greek, he studied in the local gymnasium, learning physical skills, social discourse, reading, writing, arithmetic, poetry, and music. He then moved to Athens for further studies, where he was taught stoicism by Zeno of Citium, the founder of stoicism. He also studied under the head of the Platonic Academy, Arcesilaus of Pitane. He wrote his first scholarly work, Platonikos, building upon Plato's philosophies in Mathematics.

At the age of 31, Eratosthenes was appointed as chief librarian at the Library of Alexandria. He spent time increasing the stock of available books there. He also fixed literary and political events’ dates in the texts to make them more accurate. His teachers included Ariston of Chios, who was also once a student of Zeno, the scholar Lysanias of Cyrene, and the Stoic school of philosophy's founder. Eratosthenes was a student under the scholar and poet Callimachus, also born in Cyrene.

Family, Romance, And Relationships

Who was Eratosthenes's partner?

Eratosthenes did not have a known partner.

Career And Professional Highlights

Best Known For…

Eratosthenes, a polymath with significant contributions to various fields such as mathematics, astronomy, geography, music, and poetry, studied in Alexandria, the greatest learning center in North Africa at the time. When he was 31, King Ptolemy III Eurergetes appointed him as the Chief Librarian at the Great Library of Alexandria, replacing Callimachus, his grammar tutor.

In this position, he produced works covering various topics, including geography, chronology, mathematics, literature, philosophy, criticism, poetry, grammar, and old comedies. In mathematics, he is best known for his sieve, the Sieve of Eratosthenes. The sieve is an ancient algorithm for isolating all the prime numbers in any given limit by constantly marking all the multiples of each prime within the limit as composite numbers, starting with the smallest prime number, 2. This method effectively separates prime numbers from every composite number, as it eliminates all the multiples of the discovered primes. Eratosthenes wrote two mathematics books, although these have been lost since ancient times.

Eratosthenes measured and documented the Earth’s circumference. He was told that a certain well in Syene was illuminated to its bottom on the summer solstice, a phenomenon that did not occur in Alexandria. He utilized the established distance between the two cities to deduce the circumference of the Earth. His resulting calculation of 252,000 stadia stood as the most accurate measurement of its kind during that period and for many subsequent centuries.

In addition to his mathematical and geographical contributions, Eratosthenes also made significant strides in the field of astronomy. Eratosthenes created the armillary sphere around 255 BC, which was one of the most important instruments in astronomy for determining the positions of celestial objects until the invention of the telescope.

Eratosthenes merged astronomy and poetry in his work named 'Hermes', which provided a historical description of the fixed stars. He also wrote 'Erigone', describing the suicide of Erigone, the daughter of Icarius. He authored 'Chronographies', a text that scientifically depicted significant dates, beginning with the Trojan War. Eratosthenes wrote 'Olympic Victors', a chronological record of the winners of the Olympic Games, and created a whole section devoted to the examination of Homer, the legendary ancient Greek poet and author of 'The Iliad' and 'The Odyssey'.

Towards the end of his life, Eratosthenes contracted ophthalmia and became blind around 195 BC. Losing the ability to read and observe nature, Eratosthenes voluntarily starved himself. He died in 194 BCE at the age of 82 in Alexandria.

Eratosthenes' legacy continues to influence modern science and mathematics. His algorithm for finding all the primes, known as the Sieve Of Eratosthenes, is still important in modern number theory. His accurate calculation of the Earth's circumference was an achievement that demonstrated the power of observation, deduction, and mathematics.

Other Interesting Eratosthenes Facts And Trivia

  • Eratosthenes criticized Aristotle for claiming that humanity was divided into Greeks and barbarians. He argued that there was good and bad in every nation.
  • For nearly 1800 years, before the invention of the telescope, the armillary sphere was the primary instrument in astronomy for establishing the positions of stars.
  • His estimation of the Earth's circumference might have deviated between 0.5 to 17 percent from the value acknowledged by contemporary astronomers, yet it fell within the approximate range.
  • Christopher Columbus used Eratosthenes' calculation of the Earth's circumference as proof that reaching far-off lands by sea would be possible.

Eratosthenes Birthday & Fun Facts Facts



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Scientific Writer, Astronomer, Poet, Librarian, Mathematician, Geographer, Music Theorist, Philosopher
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Written by Akinwalere Olaleye

Bachelor of Arts specializing in English Literature

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Akinwalere OlaleyeBachelor of Arts specializing in English Literature

As a highly motivated, detail-oriented, and energetic individual, Olaleye's expertise lies in administrative and management operations. With extensive knowledge as an Editor and Communications Analyst, Olaleye excels in editing, writing, and media relations. Her commitment to upholding professional ethics and driving organizational growth sets her apart. She has a bachelor's degree in English Literature from the University of Benin, Edo State. 

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