Le systme de l'Incanto des gales du march  Venise offers the first complete analysis of the medieval Venetian system of auctioning (Incanto) the state-owned galleys for commercial use. The Incanti (auction records) reveal a pattern of progressive intervention by the state in sea-trading and the evolution of a corpus of statutes governing private navigation. The work traces the growth and interdependency of the 8 state shipping lines. By establishing the infrastructure necessary for international commerce, the state (or rather the patriciate) enabled the involvement in trade -- in roles ranging from sponsor to captain to arquebusier -- of a large number of nobles with only modest capitals. This study also examines the structures of such participation (patrician family associations) and shows how these defined the career patterns of nobles and guided the emergence of a noble merchant oligarchy in medieval Venice.