In the middle Po valley of the tenth century fishing was a highly complex and carefully organized activity. The Honorantie Civitatis Papie, the document attesting to this organization, refers to a substantial association of fishers at Pavia who selected one of their number to be chief magistrate and principal interlocutor of the royal government. The fishers also maintained a sizable fleet of boats (at least sixty of them) from which to fish and with which to reach fisheries and traps set in the Po's waters, whose regimen suited numerous fish species. The association collectively paid a monthly tribute in money to its magistrate, presumably a fraction of the income generated by the sale of the fishers' daily catch. The magistrate was supposed to handle this fund in such a way that the royal table in the capital city could be supplied with fresh fish delicacies on demand. The “magister” did not take fish tributes from fishers “in good standing” because of the perishable nature of this commodity. In fact the complicated taxation scheme of the Honorantie aimed at flexibility for the rulers, who preferred incorruptible silver coins paid regularly to payments in fish which might not always be needed. Thus the Honorantie reveals a sophisticated world of inland, fresh-water fishing in Italy's greatest river at the close of the period under consideration in this study. There were specialized workers and techniques, developed markets and taxation, elaborate hierarchies, and complex consumption patterns, all attuned to the riverine ecosystems of the area. The Honorantie is uniquely detailed, but similar fishers' brotherhoods appear fleetingly in roughly contemporary documents from Lucca and Ravenna.