Koine Greek (Greek: Κοινὴ Ἑλληνική, IPA: [ciˈni eliniˈci], "common Greek", or ἡ κοινὴ διάλεκτος, IPA: [i ciˈni ˈðialektos], "the common ialect") is the popular form of Greek which emerged in post-Classical antiquity (c.300 BC – AD 300), and marks the third period in the history of the Greek language. Other names are Alexandrian, Hellenistic, Common, or New Testament Greek. Koine is important not only to the history of the Greeks for being their first common dialect and main ancestor of modern Greek, but also for its impact on Western culture as a lingua franca for the Mediterranean. It was also the original language of the New Testament of the Christian Bible as well as the medium for the teaching and spreading of Christianity. Koine Greek was unofficially the second language in the Roman Empire.