On the life of Poseidonios there is but little reliable information elucidating the theme of this paper. The probable years of his birth and death are 135 and 51 B.C. About his background nothing is known except that Apameia in Syria was his place of origin. In view of the mixed population of that country one might surmise the presence of non-Hellenic ethnical components in his ancestry, but nothing is known about this. He was a disciple of the stoic philosopher Panaitios of Rhodes, probably at Athens; afterwards he became himself the head of the stoic school in Rhodes, where he must have acquired the citizenship, for he acted as a magistrate (‘prytanis’) and as an ambassador of the city. Strabo's praise of the exemplary social-welfare work at Rhodes (14, 653) seems to be derived from Poseidonios; in any case it is characteristic of Poseidonios' interest in social problems (see below p. 48).