Syrian-born Greek philosopher, scientist and polymath Posidonius (c. 135 - c. 51 BC) studied in Athens and spent many years travelling and carrying out scientific research across Europe and northern Africa. He eventually settled in Rhodes, where he became an active citizen.
Sent to Rome in 86 BC as an envoy, he befriended Cicero and other leading figures. As a polymath in the tradition of Aristotle and Eratosthenes, he wrote extensively on various subjects from astronomy to philosophy, including geometry, geography, history and meteorology. However, only fragments of his work survive.
See here for a more detailed biographical sketch.