Posidonius "of Apameia" or "of Rhodes", was a Greek politician, astronomer, astrologer, geographer, historian, mathematician, and teacher native to Apamea, Syria. He was considered the most learned man of his time and, possibly, of the entire Stoic school. After a period learning Stoic philosophy from Panaetius in Athens, he spent many years in travel and scientific researches in Spain, Africa, Italy, Gaul, Liguria, Sicily and on the eastern shores of the Adriatic. He settled as a teacher at Rhodes where his fame attracted numerous scholars. Next to Panaetius he did most, by writings and personal lectures, to spread Stoicism to the Roman world, and he became well known to many leading men, including Pompey and Cicero.

Apamea, on the right bank of the Orontes River, was an ancient Greek and Roman city. It was the capital of Apamene under the Macedonians, became the capital and Metropolitan Archbishopric of late Roman province Syria Secunda, again in the crusader period.