CivAtlasHistory reader

History of science / 1800 BCE — 499 CE

Number & Sky

Observation and reasoning

Tablets, papyri, geometry and medical writings turn practical observations into knowledge that can be shared.

Open science atlas11 selected stories
Thematic illustration of geometry, the sky and scientific instruments; not a documented historical scene.
An original diagram evokes this era’s themes. It is not a historical artifact, a documented scene or a picture of this particular event.

Selected stories

  1. c. 1800 BCE · Mathematics

    A Babylonian tablet records right-triangle numbers

    Plimpton 322 preserves a sexagesimal number table revealing sophisticated relationships between the sides of right triangles.

  2. c. 1550 BCE · Mathematics

    The Rhind papyrus teaches fractions and measurement

    The scribe Ahmose copied mathematical problems involving division, fractions, areas and volumes, drawing on earlier material.

  3. c. 400 BCE (core texts) · Life sciences

    The Hippocratic writings follow symptoms and surroundings

    Hippocratic writings connect illness with symptoms, diet and surroundings, through texts by multiple authors rather than one unified voice.

  4. c. 300 BCE · Mathematics

    Euclid's Elements builds chains of proof

    The Elements organizes earlier geometry and number theory into propositions derived from definitions and basic assumptions.

  5. c. 3rd century BCE · Astronomy

    Aristarchus imagines a moving Earth

    Aristarchus proposed a Sun-centred model, known mainly through other ancient authors because his heliocentric text is lost.

  6. c. mid-3rd century BCE · Mathematics

    Archimedes bounds a circle with polygons

    Inscribed and circumscribed polygons let Archimedes place the circumference-to-diameter ratio between demonstrable upper and lower bounds.

  7. 132 CE (recorded construction year) · Earth sciences

    Zhang Heng's seismoscope makes earthquakes an instrument problem

    Historical accounts describe an instrument in Luoyang that indicated earthquake direction. Its original mechanism is lost and reconstructions remain debated.

  8. c. 150 CE · Astronomy

    Ptolemy calculates the sky with geometry

    The Almagest combines observations, a star catalogue and geometric models to predict celestial positions within a stationary-Earth framework.

  9. c. 170 CE (2nd-century writings) · Life sciences

    Galen's anatomy combines observation with analogy

    Animal dissection and clinical experience supported Galen's influential anatomy, but extending animal structures to humans also produced errors.

  10. 263 CE · Mathematics

    Liu Hui explains why the Nine Chapters' procedures work

    Liu Hui comments on inherited mathematical procedures, connecting calculation with geometric reasoning, including a method for approximating circles.

  11. 499 CE · Astronomy

    The Aryabhatiya puts numerical tables to work in astronomy

    Aryabhata's Sanskrit verses organize mathematical astronomy, including sine tables, eclipse calculations and an account of Earth's rotation.

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