Eratosthenes
Alexandrian polymath who calculated Earth's circumference and linked constellations to myths in his Catasterisms
The Meaning of Eratosthenes
Eratosthenes of Cyrene (c. 276-194 BCE) was one of antiquity's most versatile scholars: mathematician, geographer, astronomer, poet, and head of the Library of Alexandria. He famously calculated the Earth's circumference with remarkable accuracy using the angle of shadows at Alexandria and Syene during the summer solstice. For mythology, his most relevant work is the Catasterisms — a treatise explaining the mythological origins of the constellations, linking each star group to a Greek legend. Orion the hunter, Callisto transformed into the Great Bear, Ariadne's crown placed among the stars by Dionysus — Eratosthenes systematised these celestial myths. The work connects Greek mythology to the night sky in ways that persisted through astronomical naming conventions to the present.
Parents
None recorded
Symbols
Fun Fact
Eratosthenes calculated Earth's circumference in the third century BCE and came within two percent of the correct value
Words We Inherited
English words and phrases that trace back to this myth. See our full guide to English words from Greek mythology.
Explore Further
Geography
💭 conceptLanguage and science
An English word for the study of the earth's surface, places, and peoples, derived from the Greek geographia meaning earth-writing or earth-description
Strabo
💭 conceptGeography, ethnography
Greek geographer whose seventeen-book Geography records mythological traditions alongside physical descriptions
Ganymede
💭 conceptAstronomy and mythology
The largest moon in the solar system, named after Ganymede, the beautiful Trojan prince abducted by Zeus to serve as cupbearer of the gods on Olympus
Uranus
💭 conceptAstronomy and mythology
The seventh planet from the Sun, named after Ouranos, the primordial Greek god of the sky and the earliest supreme deity in the mythological genealogy
Jupiter
💭 conceptAstronomy and mythology
The largest planet in the solar system, named after Jupiter, the Roman king of the gods identified with the Greek Zeus, because of its commanding size and brightness
Catasterism
💭 conceptTransformation into a constellation
Catasterism was the process by which a mortal or creature was placed among the stars.
Constellation Orion
💭 conceptastronomy, hunting
The giant hunter of Greek mythology, placed among the stars by Zeus or Artemis, forming one of the most recognisable constellations in the night sky.
Palaephatus
💭 conceptRationalism, myth interpretation
Ancient rationaliser who explained myths as misunderstood historical events in On Unbelievable Tales
Venus
💭 conceptAstronomy and mythology
The second planet from the Sun and the brightest natural object in the night sky after the Moon, named after Venus, the Roman goddess of love identified with the Greek Aphrodite
Callisto
💭 conceptAstronomy and mythology
A moon of Jupiter named after Callisto, the nymph companion of Artemis who was transformed into a bear and placed among the stars as the constellation Ursa Major
Saturn
💭 conceptAstronomy and mythology
The sixth planet from the Sun, named after Saturn, the Roman god of agriculture and time identified with the Greek Titan Kronos, father of Zeus
Triton
💭 conceptAstronomy and mythology
The largest moon of Neptune, named after Triton, the merman son of Poseidon, notable for being the only large moon in the solar system that orbits in the opposite direction to its planet