 In Roman times, the Gradac area was most likely the seat of the Roman civitas Biston, which as a coastal center belonged to the colony of Narona, an important Roman stronghold on what is now Croatian territory.At the locality of Gradina a cornice fragment of the monumental building from the 2nd-3rd century was found, as well as Roman coin pieces.Near the Laguna hotel were found many tombs, hence it is thought that on this location there was once a Roman necropolis.