---
title: "Science in classical antiquity"
chunk: 5/6
source: "https://en.wikipedia.org/wiki/Science_in_classical_antiquity"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T03:10:44.265759+00:00"
instance: "kb-cron"
---

Advances in mathematical astronomy also took place during the Hellenistic age. Aristarchus of Samos (310–230 BC) was an ancient Greek astronomer and mathematician who presented the first known heliocentric model that placed the Sun at the center of the known universe, with the Earth revolving around the Sun once a year and rotating about its axis once a day. Aristarchus also estimated the sizes of the Sun and Moon as compared to Earth's size, and the distances to the Sun and Moon. His heliocentric model did not find many adherents in antiquity but did influence some early modern astronomers, such as Nicolaus Copernicus, who was aware of the heliocentric theory of Aristarchus.
In the 2nd century BC, Hipparchus discovered precession, calculated the size and distance of the Moon and invented the earliest known astronomical devices such as the astrolabe. Hipparchus also created a comprehensive catalog of 1020 stars, and most of the constellations of the northern hemisphere derive from Greek astronomy. It has recently been claimed that a celestial globe based on Hipparchus's star catalog sits atop the broad shoulders of a large 2nd-century Roman statue known as the Farnese Atlas.

== Roman era ==

Science during the Roman Empire was concerned with systematizing knowledge gained in the preceding Hellenistic age and the knowledge from the vast areas the Romans had conquered. It was largely the work of authors active in this period that would be passed on uninterrupted to later civilizations.
Even though science continued under Roman rule, Latin texts were mainly compilations drawing on earlier Greek work. Advanced scientific research and teaching continued to be carried on in Greek. Such Greek and Hellenistic works as survived were preserved and developed later in the Byzantine Empire and then in the Islamic world. Late Roman attempts to translate Greek writings into Latin had limited success (e.g., Boethius), and direct knowledge of most ancient Greek texts only reached western Europe from the 12th century onwards.

=== Pliny ===
Pliny the Elder published the Naturalis Historia in 77 AD, one of the most extensive compilations of the natural world which survived into the Middle Ages. Pliny did not simply list materials and objects but also recorded explanations of phenomena. Thus he is the first to correctly describe the origin of amber as being the fossilized resin of pine trees. He makes the inference from the observation of trapped insects within some amber samples.
Pliny's work is divided neatly into the organic world of plants and animals, and the realm of inorganic matter, although there are frequent digressions in each section. He is especially interested in not just describing the occurrence of plants, animals and insects, but also their exploitation (or abuse) by man. The description of metals and minerals is particularly detailed, and valuable as being the most extensive compilation still available from the ancient world. Although much of the work was compiled by judicious use of written sources, Pliny gives an eyewitness account of gold mining in Spain, where he was stationed as an officer. Pliny is especially significant because he provides full bibliographic details of the earlier authors and their works he uses and consults. Because his encyclopaedia survived the Dark Ages, we know of these lost works, even if the texts themselves have disappeared. The book was one of the first to be printed in 1489, and became a standard reference work for Renaissance scholars, as well as an inspiration for the development of a scientific and rational approach to the world.

=== Hero ===
Hero of Alexandria was a Greco-Egyptian mathematician and engineer who is often considered to be the greatest experimenter of antiquity. Among his most famous inventions was a windwheel, constituting the earliest instance of wind harnessing on land, and a well-recognized description of a steam-powered device called an aeolipile, which was the first-recorded steam engine.

=== Galen ===
The greatest medical practitioner and philosopher of this era was Galen, active in the 2nd century AD. Around 100 of his works survive—the most for any ancient Greek author—and fill 22 volumes of modern text. Galen was born in the ancient Greek city of Pergamon (now in Turkey), the son of a successful architect who gave him a liberal education. Galen was instructed in all major philosophical schools (Platonism, Aristotelianism, Stoicism and Epicureanism) until his father, moved by a dream of Asclepius, decided he should study medicine. After his father's death, Galen traveled widely searching for the best doctors in Smyrna, Corinth, and finally Alexandria.
Galen compiled much of the knowledge obtained by his predecessors, and furthered the inquiry into the function of organs by performing dissections and vivisections on Barbary apes, oxen, pigs, and other animals. In 158 AD, Galen served as chief physician to the gladiators in his native Pergamon, and was able to study all kinds of wounds without performing any actual human dissection. It was through his experiments, however, that Galen was able to overturn many long-held beliefs, such as the theory that the arteries contained air which carried it to all parts of the body from the heart and the lungs. This belief was based originally on the arteries of dead animals, which appeared to be empty. Galen was able to demonstrate that living arteries contain blood, but his error, which became the established medical orthodoxy for centuries, was to assume that the blood goes back and forth from the heart in an ebb-and-flow motion.
Anatomy was a prominent part of Galen's medical education and was a major source of interest throughout his life. He wrote two great anatomical works, On anatomical procedure and On the uses of the parts of the body of man. The information in these tracts became the foundation of authority for all medical writers and physicians for the next 1300 years until they were challenged by Vesalius and Harvey in the 16th century.

=== Ptolemy ===