Dionysos had to jump into the sea in order to escape from Lycurgos; in another episode, the god was attacked by Tyrrhenian pirates who were transformed into dolphins. These two little known episodes of the myth of the god are depicted, directly or indirectly, on the pavements of reception halls. We will first study this iconography on the mosaics of the Hellenistic period, and then on those of the Imperial period, and pay particular attention to the scenes of the marine triumph of Dionysos (Dion, Corinth) and on the depiction of black swimmers (Pompeii, North Italy, the Narbonnaise). In line with the works of Jean-Pierre Darmon, we will inquire into the transmission of iconographic schemes through the ages, first in the Greek koine and then in the Roman Empire; and, finally, into their meaning according to architectural contexts in which they are found.