“In the 3rd century BC, Aristophanes of Byzantium invented a system of single dots rel=”nofollow” (distinctiones) that separated verses (colometry), and indicated the amount of breath needed to complete each fragment of text, when reading aloud. (1) The different lengths were signified by a dot at the bottom, middle, or top of the line. For a short passage (akomma), a media distinctio dot was placed mid-level ( · ). This is the origin of the concept of a comma, although the name came to be used for the mark itself, instead of the clause it separated.
The mark used today is descended from a diagonal slash, or virgula suspensiva ( / ), used from the 13th to 17th centuries to represent a pause, and was first used by Aldus Manutius.” (2) (3)
Found at Wikipedia.