Roman maritime commerce and especially the food supply of Rome have
long been studied from a merely juridical point of view, ignoring the actual
persons involved in the commercial organisation, e.g. navicularii and negotiatores.
As very few of these merchants are known from Roman epigraphy,
one has to depend on research results from underwater archaeology and
amphorae studies. Of particular interest are the tituli picti on Dressel 20, oil
amphorae from southern Spain. They introduce to us various families of oil
merchants, whose commercial networks stretched from Baetica over Gallia
Narbonensis to Ostia and Rome.