Eratosthenes of Cyrene was a Greek mathematician, geographer, poet, astronomer, and music theorist. source

Eratosthenes of Cyrene was a Greek mathematician, geographer, poet, astronomer, and music theorist.

Eratosthenes was a man of learning, becoming the chief librarian at the Library of Alexandria. He invented the discipline of geography, including the terminology used today. source

Eratosthenes was a man of learning, becoming the chief librarian at the Library of Alexandria. He invented the discipline of geography, including the terminology used today.

Eratosthenes is best known for being the first person to calculate the circumference of the Earth, which he did by applying a measuring system using stadia, a standard unit of measure during that time period. source

Eratosthenes is best known for being the first person to calculate the circumference of the Earth, which he did by applying a measuring system using stadia, a standard unit of measure during that time period.

Eratosthenes's calculation was remarkably accurate. He was also the first to calculate the tilt of the Earth's axis (again with remarkable accuracy). source

Eratosthenes's calculation was remarkably accurate. He was also the first to calculate the tilt of the Earth's axis (again with remarkable accuracy).

Additionally, Eratosthenes may have accurately calculated the distance from the Earth to the Sun and invented the leap day. source

Additionally, Eratosthenes may have accurately calculated the distance from the Earth to the Sun and invented the leap day.

Eratosthenes created the first map of the world, incorporating parallels and meridians based on the available geographic knowledge of his era. source

Eratosthenes created the first map of the world, incorporating parallels and meridians based on the available geographic knowledge of his era.

Eratosthenes was the founder of scientific chronology; he endeavored to revise the dates of the chief literary and political events from the conquest of Troy. source

Eratosthenes was the founder of scientific chronology; he endeavored to revise the dates of the chief literary and political events from the conquest of Troy.

In number theory, Eratosthenes introduced the sieve of Eratosthenes, an efficient method of identifying prime numbers. source

In number theory, Eratosthenes introduced the sieve of Eratosthenes, an efficient method of identifying prime numbers.

Nonetheless, Eratosthenes's devotees nicknamed him Pentathlos after the Olympians who were well rounded competitors, for he had proven himself to be knowledgeable in every area of learning. source

Nonetheless, Eratosthenes's devotees nicknamed him Pentathlos after the Olympians who were well rounded competitors, for he had proven himself to be knowledgeable in every area of learning.

Eratosthenes yearned to understand the complexities of the entire world. source

Eratosthenes yearned to understand the complexities of the entire world.

The son of Aglaos, Eratosthenes was born in 276 BC in Cyrene. Now part of modern-day Libya, Cyrene had been founded by the Greeks centuries earlier and became the capital of Pentapolis (North Africa), a country of five cities. source

The son of Aglaos, Eratosthenes was born in 276 BC in Cyrene. Now part of modern-day Libya, Cyrene had been founded by the Greeks centuries earlier and became the capital of Pentapolis (North Africa), a country of five cities.

Like any young Greek, Eratosthenes would have studied in the local gymnasium, where he would have learned physical skills and social discourse as well as reading, writing, arithmetic, poetry, and music. source

Like any young Greek, Eratosthenes would have studied in the local gymnasium, where he would have learned physical skills and social discourse as well as reading, writing, arithmetic, poetry, and music.

Eratosthenes went to Athens to further his studies. There he was taught Stoicism by its founder, Zeno of Citium, in philosophical lectures on living a virtuous life. source

Eratosthenes went to Athens to further his studies. There he was taught Stoicism by its founder, Zeno of Citium, in philosophical lectures on living a virtuous life.

Eratosthenes then studied under Ariston of Chios, who led a more cynical school of philosophy. He also studied under the head of the Platonic Academy, who was Arcesilaus of Pitane. source

Eratosthenes then studied under Ariston of Chios, who led a more cynical school of philosophy. He also studied under the head of the Platonic Academy, who was Arcesilaus of Pitane.

Eratosthenes was a man of many perspectives and investigated the art of poetry under Callimachus. He was a talented and imaginative poet. source

Eratosthenes was a man of many perspectives and investigated the art of poetry under Callimachus. He was a talented and imaginative poet.

Eratosthenes wrote poems: one in hexameters called Hermes, illustrating the god's life history; and another, in elegiacs called Erigone, describing the suicide of the Athenian maiden Erigone (daughter of Icarius). source

Eratosthenes wrote poems: one in hexameters called Hermes, illustrating the god's life history; and another, in elegiacs called Erigone, describing the suicide of the Athenian maiden Erigone (daughter of Icarius).

Eratosthenes wrote Chronographies, a text that scientifically depicted dates of importance, beginning with the Trojan War. This work was highly esteemed for its accuracy. source

Eratosthenes wrote Chronographies, a text that scientifically depicted dates of importance, beginning with the Trojan War. This work was highly esteemed for its accuracy.

Eratosthenes also wrote Olympic Victors, a chronology of the winners of the Olympic Games. It is not known when he wrote his works, but they highlighted his abilities. source

Eratosthenes also wrote Olympic Victors, a chronology of the winners of the Olympic Games. It is not known when he wrote his works, but they highlighted his abilities.

Eratosthenes, then thirty years old, accepted Ptolemy's invitation and traveled to Alexandria, where he lived for the rest of his life. source

Eratosthenes, then thirty years old, accepted Ptolemy's invitation and traveled to Alexandria, where he lived for the rest of his life.

As head of the library Eratosthenes tutored the children of Ptolemy, including Ptolemy IV Philopator who became the fourth Ptolemaic pharaoh. source

As head of the library Eratosthenes tutored the children of Ptolemy, including Ptolemy IV Philopator who became the fourth Ptolemaic pharaoh.

Legend has it that Eratosthenes went blind and died by starving himself when he was 80 to 82 years old. source

Legend has it that Eratosthenes went blind and died by starving himself when he was 80 to 82 years old.

Archimedes dedicated his book The Method to Eratosthenes, knowing Eratosthenes's love for learning and mathematics. source

Archimedes dedicated his book The Method to Eratosthenes, knowing Eratosthenes's love for learning and mathematics.

Eratosthenes proposed a simple algorithm for finding prime numbers. This algorithm is known in mathematics as the Sieve of Eratosthenes. source

Eratosthenes proposed a simple algorithm for finding prime numbers. This algorithm is known in mathematics as the Sieve of Eratosthenes.

Eratosthenes was one of the most pre-eminent scholarly figures of his time, and produced works covering a vast area of knowledge before and during his time at the Library. source

Eratosthenes was one of the most pre-eminent scholarly figures of his time, and produced works covering a vast area of knowledge before and during his time at the Library.

He was also very proud of his solution for Doubling the Cube. His motivation was that he wanted to produce catapults. Eratosthenes constructed a mechanical line drawing device to calculate the cube, called the mesolabio. source

He was also very proud of his solution for Doubling the Cube. His motivation was that he wanted to produce catapults. Eratosthenes constructed a mechanical line drawing device to calculate the cube, called the mesolabio.

Eratosthenes had invented geography. He created terminology that is still used today. He placed grids of overlapping lines over the surface of the Earth. source

Eratosthenes had invented geography. He created terminology that is still used today. He placed grids of overlapping lines over the surface of the Earth.