The year of his birth is uncertain. He was born a slave. We do know that he was born early enough to be teaching philosophy by around AD 93, when Domitian banished all philosophers from Rome, because he was among those who left the city under that decree. Around 108 AD, he described himself to Arrian as being an old man cf. Discourses, i.9.10; i.16.20; ii.6.23; etc.
He apparently was alive in the reign of Hadrian (117–138). Marcus Aurelius (born AD 121) was an admirer, but never met him, and Aulus Gellius (ii.18.10) writing mid-second century, speaks of him as if he belonged to the recent past.