Greek accents

The invention of accent marks as a guide to the pronunciation of classical Greek, denoting not stress but the pitch of the voice, has been attributed to the Alexandrian scholar Aristophanes of Byzantium c.200 BC. It may have been prompted by the need to guide Greek speakers in the pronunciation of by then unfamiliar words (e.g. in Homeric epic) and to teach the language to foreigners. The low tones are left unaccented, except in a few cases where the grave accent is used, and the high and compound tones are indicated by the acute and circumflex accents.