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.

Posidonius in his writings on meteorology followed Aristotle.

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 '.

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.

Cleomedes ' book is criticized by most modern astronomers as being poorly written — it is valued primarily for preserving, apparently verbatim, much of Posidonius ' writings on astronomy ( none of Posidonius ' books have survived to the modern day ).

Plutarch relates several opinions on the end of C. Marius: one, from Posidonius, holds that Marius contracted pleurisy ; Gaius Piso has it that Marius walked with his friends and discussed all of his accomplishments with them, adding that no intelligent man ought leave himself to Fortune.

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.

In Hispania, on the Atlantic coast at Gades ( the modern Cadiz ), Posidonius could observe tides much higher than in his native Mediterranean.

Posidonius wrote a geographic treatise on the lands of the Celts which has since been lost, but which is referred to extensively ( both directly and otherwise ) in the works of Diodorus of Sicily, Strabo, Caesar and Tacitus ' Germania.

Posidonius wrote on physics ( including meteorology and physical geography ), astronomy, astrology and divination, seismology, geology and mineralogy, hydrology, botany, ethics, logic, mathematics, history, natural history, anthropology, and tactics.

Although it is not certain, Posidonius may have written a commentary on Plato's Timaeus.

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 ).

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.

For example, Posidonius considered the climate of Arabia and the life-giving strength of the sun, tides ( taken from his book on the oceans ), and climatic theory to explain people ’ s ethnic or national characters.

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.

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.

The crater Posidonius on the Moon is named after him.

Identified authors on whose works he drew include Hecataeus of Abdera, Ctesias of Cnidus, Ephorus, Theopompus, Hieronymus of Cardia, Duris of Samos, Diyllus, Philistus, Timaeus, Polybius, and Posidonius.

Other ancient historians and philosophers believing in the existence of Atlantis were Strabo and Posidonius.

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

In addition to the rational faculties, Posidonius taught that the human soul had faculties that were spirited ( anger, desires for power, possessions, etc.

In Stoic physics, Posidonius advocated a theory of cosmic " sympathy " ( sumpatheia ), the organic interrelation of all appearances in the world, from the sky to the earth, as part of a rational design uniting humanity and all things in the universe, even those that were temporally and spatially separate.

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

Well known eclectics in Greek philosophy were the Stoics Panaetius and Posidonius, and the New Academics Carneades and Philo of Larissa.

These were named for the crater Daniell, a small formation north of Posidonius that is encircled by the Lacus Somniorum.

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.

Franz Boll noticed the arguments were paralleled in older sources, particularly those of the Stoic philosopher Posidonius ( 135 BCE – AD 51 BCE ).

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 ).

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.

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.

Later writers — Posidonius, Diodorus Siculus, Strabo and others — call them smallish islands off (" some way off ," Strabo says ) the northwest coast of the Iberian Peninsula, which contained tin mines or, according to Strabo, tin and lead mines.

Written studies of the Celts, their cultures and their languages go back to classical Greek and Latin accounts, possibly beginning with Hecataeus in the 6th century BC and best known through such authors as Polybius, Posidonius, Pausanias, Diodorus Siculus, Julius Caesar and Strabo.

Posidonius constructed an orrery, possibly similar to the Antikythera mechanism.

Posidonius also affirmed the Stoic doctrine of the future conflagration.

Posidonius also calculated the size and distance of the Moon.

Six classical Greek authors also came to identify these mythical people at the back of the North Wind with their Celtic neighbours in the north: Antimachus of Colophon, Protarchus, Heraclides Ponticus, Hecataeus of Abdera, Apollonius of Rhodes and Posidonius of Apamea.

( See also Gassendi and Posidonius for similar features.

A passage in his works referring to the Annus Vagus ( Wandering Year ) of the Egyptian calendar of 120 years before his own time, has been used to imply a date of c. 70 BC for the time of writing, which would be consistent with the idea that he may have been a pupil of Posidonius, but a date as late as 50 AD has also been suggested.

He also wrote a commentary on Posidonius ' work On Meteorology.

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.

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.

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.