“This active trade was maintained by well-organized ports on sea and river, with large fleets to serve them, and by a fine road network. From earliest times merchants and craftsmen organized themselves into corporations not unlike medieval guilds, and a the state came more and more to concern itself with commerce these became important features in an increasingly regimented society. In sea-ports like Narbonne and Arles the most imposing corporations were those of the traders by sea, the powerful navicularii; at river ports there were the nautae, the river shippers, barge owners, etc.—generally men of substance and weight in their city. Rather less august are the corporations of utricularii, lightermen, boatmen, etc., and the ratarii who were concerned in the building and use of rafts and may have worked ferries.

The utricularii seem to have been distinguished by their boats or rafts made buoyant by inflated skins, very useful in the navigation of the lagoons of the south. Such boats had been used by Hannibal when he crossed the Rhone. Many inscriptions of utricularii have been found, particularly in Provence, and at Narbonne and up the trubutaries of the Rhone (e.g. at Vaison on the Ouvèze). One intersting case is an identity disc from Cavaillon, with on one side the inscription Colle(gium) utri(clariorum) Cab(ellesnsium) L(uci) Valer(ii) Succes(si), and on the other a little model of an inflated skin.

Heavy traffic went as far as possible by river, and the nautae are extremely important all over Gaul and are known on the Rhone, Saône, Seine, Durance, Ardèche, Ouvèze, Loire, Aar, Moselle, Rhine. The nautae were responible for the portage of goods from one river to another, so owned wagons as well as ships and barges. A shipper from Vannes has left an inscription at Lyons showing that he belonged to the corporation of nautae both of Loire and the Saône.

There were also corporations of hauliers—helciarii whose painful task it was to tow barges upstream, and some attractive sculptures show them at work. Sidonius writes of the boatmen he heard singing as the towed their cargoes through Lyons.”
[Roman-Gaul, Brogan,1953]