Travels and Writings

Over the course of his lifetime, his travels took him across Greece, through Italy, from Sicily to Liguria, into Gaul (modern-day France) and the Iberian Peninsula, and around North Africa. Heading east from Italy, he covered the eastern shores of the Adriatic and Dalmatia. 

His travels provided Posidonius with sights and experiences that informed his subsequent writings. 

Higher tides than those in the Mediterranean at Gades (Cadiz) prompted a hypothesis that linked daily tides to the Moon's orbit, tidal heights to the cycles of the Moon, and yearly tidal cycles with the equinoxes and solstices.

His travels in Gaul resulted in a geographic treatise on the Celts and their territories which may have been lost but was extensively cited in the works of Strabo, Caesar and Tacitus.

Posidonius's writings and lectures made him famous across the Graeco-Roman world as he attempted to create a unified system for understanding the universe which would also explain human behaviour.

His written work covered astronomy, astrology and divination, the physical sciences including meteorology, physical geography, seismology, geology, hydrology, and mineralogy, botany and natural history, mathematics, history, anthropology, logic and ethics. 

Although none of his work survives intact, the titles and subjects of many of his works are known through references by other writers.  

Fragments of his work on astronomy, for example, survive through the treatise by Cleomedes, On the Circular Motions of the Celestial Bodies, while writers such as Strabo provide details of Posidonius’s geographical work and its relation to those who went before and after him through their commentary:

Strabo on Posidonius

© Ian Hughes 2017