Attic and Koine (again...)

Gryllus Maior

Well-known member
"The Greek Koine, or 'common dialect', which evolved as an international variety of Attic, the dialect of ancient Athens, during the period of the Athenian Empire and the Macedonian expansion...had become the sole official, technical and and scientific language of the extensive Greek speaking community of the eastern Mediterranean, and as such remained the 'standard' form of Greek in Roman times, a status which it retained into late antiquity and beyond."

-- Clarkson, James and Horrocks, Geoffrey, The Blackwell History of the Latin Language (Wiley-Blackwell, 2011), p. 184.