The sixteenth-century Venetian Republic not only had more permanent diplomatic representatives than any other European state, it was also unique in requiring its ambassadors to deliver a final report, or relazione, on the states in which they had served. Although relazioni were intended to assist statesmen in foreign policy decision-making, over the course of the sixteenth century, ambassadors devoted increasing attention to ethnographic topics, including the customs, religious observances, foodways, and dress of the states on which they reported. Through an examination of the relazioni and their reception, this article addresses the questions of why ambassadors increasingly emphasized ethnographic material and how this new emphasis was debated among Venetian elites. The shift in the nature of diplomatic reporting did not go unnoticed by contemporaries; it engendered a vigorous debate about both the parameters of political knowledge and the nature and reliability of eyewitness versus textual authority.