The deep blue sea is the subject of speculation to this day but, in this episode, we have access to the mysteries, myths and misgivings that were associated with the ocean in the 2nd century AD. The Halieutica was written in Hexameter by the Greek poet Oppian, and dedicated to the then Roman Emperor Marcus Aurelius and his son Commodus. Emily Kneebone from the University of Nottingham has recently completed a monograph on this overlooked Epic, and she is here to tell us about the sea and its often personified, often hostile inhabitants.