According to Cicero, the Roman philosopher who was writing in the first century BC, Posidonius constructed a planetary model.

Posidonius, nicknamed " the Athlete ", was born to a Greek family in Apamea, a Hellenistic city on the river Orontes in northern Syria, and probably died in Rome or Rhodes.

Posidonius completed his higher education in Athens, where he was a student of the aged Panaetius, the head of the Stoic school.

Posidonius was celebrated as a polymath throughout the Graeco-Roman world because he came near to mastering all the knowledge of his time, similar to Aristotle and Eratosthenes.

For Posidonius, philosophy was the dominant master art and all the individual sciences were subordinate to philosophy, which alone could explain the cosmos.

Although a firm Stoic, Posidonius was, like Panaetius and other Stoics of the middle period, eclectic.

In about 90 BCE Posidonius estimated the distance to the sun ( see astronomical unit ) to be 9, 893 times the Earth's radius, which was still too small by half.

While translating stadia into modern units of distance is problematic, as an ancient stadium could measure anywhere from about 157 to around 211 meters, it is generally thought that the stadium used by Posidonius was almost exactly 1 / 10 of a modern statute mile, near the middle of the ancient range.

Posidonius was, however, wrong about the cause.

Posidonius was one of the first people to attempt to prove Euclid's fifth postulate of geometry.

In addition to his writings on geometry, Posidonius was credited for creating some mathematical definitions, or for articulating views on technical terms, for example ' theorem ' and ' problem '.

For Posidonius " history " extended beyond the earth into the sky ; humanity was not isolated each in its own political history, but was a part of the cosmos.

Of Posidonius's work on tactics, The Art of War, the Greek historian Arrian complained that it was written ' for experts ', which suggests that Posidonius may have had first hand experience of military leadership or, perhaps, utilized knowledge he gained from his acquaintance with Pompey.

In his own era, his writings on almost all the principal divisions of philosophy made Posidonius a renowned international figure throughout the Graeco-Roman world and he was widely cited by writers of his era, including Cicero, Livy, Plutarch, Strabo ( who called Posidonius " the most learned of all philosophers of my time "), Cleomedes, Seneca the Younger, Diodorus Siculus ( who used Posidonius as a source for his Bibliotheca historia Library "), and others.

Although his ornate and rhetorical style of writing passed out of fashion soon after his death, Posidonius was acclaimed during his life for his literary ability and as a stylist.

Posidonius was the major source of materials on the Celts of Gaul and was profusely quoted by Timagenes, Julius Caesar, the Sicilian Greek Diodorus Siculus, and the Greek geographer Strabo.

Posidonius met Pompey when he was Rhodes's ambassador in Rome and Pompey visited him in Rhodes twice, once in 66 BCE during his campaign against the pirates and again in 62 BCE during his eastern campaigns, and asked Posidonius to write his biography.

The King Luernios was mentioned in writing by the Greek ethnographer Posidonius.

This peak was formerly designated Posidonius Gamma ( γ ).

Posidonius measured the Earth's circumference by reference to the position of the star Canopus.

A distant precursor of Bergson can be found in the work of the pre-Christian Stoic philosopher Posidonius, who postulated a " vital force " emanated by the sun to all living creatures on the Earth's surface.

Thus Posidonius ' measure of 240, 000 stadia translates to 24, 000 miles, not much short of the actual circumference of 24, 901 miles.

However, Posidonius later revised his original calculation by correcting the distance between Rhodes and Alexandria to 3, 750 stadia, resulting in a circumference of 180, 000 Stadia, or 18, 000 miles.

Ptolemy discussed and favored this revised figure of Posidonius over Eratosthenes in his Geographia, and during the Middle Ages scholars divided into two camps regarding the circumference of the earth, identified with Eratosthenes ' calculation on the one hand and Posidonius ' 180, 000-stadium measure on the other.

Some fragments of his writings on astronomy survive through the treatise by Cleomedes, On the Circular Motions of the Celestial Bodies, the first chapter of the second book appearing to have been mostly copied from Posidonius.

World map according to ideas by Posidonius ( 150-130 B. C.

In this work, Posidonius detailed his theory of the effect on a people ’ s character by the climate, which included his representation of the " geography of the races ".

As explained by Cleomedes, Posidonius observed Canopus on but never above the horizon at Rhodes, while at Alexandria he saw it ascend as far as 7½ degrees above the horizon ( the meridian arc between the latitude of the two locales is actually 5 degrees 14 minutes ).

Like Pytheas, Posidonius believed the tide is caused by the Moon.

Posidonius did not follow Polybius's more detached and factual style, for Posidonius saw events as caused by human psychology ; while he understood human passions and follies, he did not pardon or excuse them in his historical writing, using his narrative skill in fact to enlist the readers ' approval or condemnation.

Some of Posidonius ' arguments are refuted by Josephus in Against Apion.

In prehistoric times, St Michael's Mount may have been a port for the tin trade, and Gavin de Beer made a case for it to be identified with the " tin port " Ictis / Ictin mentioned by Posidonius.

The rim of Posidonius is shallow and obscured, especially on the western edge, and the interior has been overlain by a lava flow in the past.

The northeast rim is interrupted by the smaller crater Posidonius B.

Posidonius Gamma was first observed by the lunar cartographer Julius Schmidt in 1857, who noted the similarity to the bright patch surrounding the crater Linné.

By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Posidonius.

( Two motifs in this story, the champion's portion and the beheading challenge, are mentioned by the Greek writer Posidonius as practices of the ancient Celts.

As with Posidonius, Eratosthenes ' stadium is thought to have equated to 1 / 10 of a mile, so that his measure translates to 25, 000 ( or 25, 200 ) miles.

That some of the figures Eratosthenes had used in his calculation were considerably in error became known, and Posidonius set out to get a more accurate measurement.

Other Romans who visited Posidonius in Rhodes were Velleius, Cotta, and Lucilius.

A century later, Seneca referred to Posidonius as one of those who had made the largest contribution to philosophy.

While twins have been of interest to scholars since early civilization, such as the early physician Hippocrates ( 5th c. BCE ), who attributed similar diseases in twins to shared material circumstances, and the stoic philosopher Posidonius ( 1st c. BCE ), who attributed such similarities to shared astrological circumstances, the modern history of the twin study derives from Sir Francis Galton's pioneering use of twins to study the role of genes and environment on human development and behavior.

While Pliny may have been the primary source, scholars have identified others ; among them are Caesar's Gallic Wars, Strabo, Diodorus Siculus, Posidonius, Aufidius Bassus, and numerous non-literary sources: presumably based on interviews with traders and soldiers who had ventured beyond the Rhine and Danube borders, and Germanic mercenaries in Rome.

Most pagan writers probably never read the History directly, and appear to be dependent on Posidonius of Apamea ( 135-50 BC ), who cited Berossos in his works.

Hermagoras's chief opponent was Posidonius of Rhodes, who is said to have contended with him in argument in the presence of Pompey.

The third investigation he had expressly promised at the end of the third book, but had not carried out ; and his disciple Posidonius seems to have only timidly and imperfectly supplied what was wanting ; at least Cicero, who in his books On Duties intended, not indeed to translate, but to imitate Panaetius in his own manner, in the third section of the subject, did not follow Posidonius, but declares that he had completed independently and without assistance what Panaetius had left untouched.

There is an indication that this circumstance was fairly recent ; that is, Posidonius states that the Boii, who were allegedly Celtic, were once there ( as well as in Bohemia which is named for them ).